undefined method `Password_field' error using Rail3

I am getting the following error while trying to do reset password by sending sending the link to email and open that link from that email.

Error:

NoMethodError in Admins#editpass

Showing C:/Site/swargadwar_admin/app/views/admins/editpass.html.erb where line #16 raised:

undefined method `Password_field' for #<ActionView::Helpers::FormBuilder:0x21c0108>
Extracted source (around line #16):

13:     <% end %>
14:     <p>
15:         <label for "new_pass">New Password :</label>
16:         <%= f.Password_field :password,placeholder:"Enter your new password" %>
17:     </p>
18:     <p>
19:         <label for "new_pass">Confirm New Password :</label>
Rails.root: C:/Site/swargadwar_admin

Application Trace | Framework Trace | Full Trace
app/views/admins/editpass.html.erb:16:in `block in _app_views_admins_editpass_html_erb___904659562_17338176'
app/views/admins/editpass.html.erb:2:in `_app_views_admins_editpass_html_erb___904659562_17338176'

Please check my below codes and let me to know where i did the mistake as well as try to help me to resolve this.

views/admins/editpass.html.erb

<center>
    <%= form_for :admin,:url => {:action => "setpass",:id => params[:id] } do |f| %>
    <% if @admin.errors.any? %>
        <div id="error_explanation">
        <h2><%= pluralize(@admin.errors.count, "error") %> prohibited this post from being saved:</h2>

        <ul>
        <% @admin.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
        <% end %>
        </ul>
        </div>
    <% end %>
    <p>
        <label for "new_pass">New Password :</label>
        <%= f.Password_field :password,placeholder:"Enter your new password" %>
    </p>
    <p>
        <label for "new_pass">Confirm New Password :</label>
        <%= f.Password_field :password_confirmation,placeholder:"confirm your new password" %>
    </p>
    <p>
        <%= f.submit "Submit" %>
    </p>
    <% end %>
</center> 

controller/admins_controller.rb

class AdminsController < ApplicationController
    def create_registration
        @admin=Admin.new(params[:admin])
        if @admin.save
            flash[:notice]="User has created successfully"
            flash[:color]="valid"
            redirect_to :action => "index" , :controller => 'homes'
        else
            flash[:alert]="User could not created"
            flash[:color]="invalid"
            render 'homes/index'
        end
    end
    def forget
        @admin=Admin.new
    end
    def resetpass
        @admin=Admin.find_by_email(params[:admin][:email])
        if @admin.email==params[:admin][:email]
            UserMailer.registration_confirmation(@admin).deliver
            flash[:notice]="Check your email to reset the password"
            flash[:color]="valid"
            redirect_to :action => "index" , :controller => 'homes'
        else
            flash[:alert]="Invalid email id"
            flash[:color]="invalid"
            render 'homes/index'
        end
    end
    def editpass
        @admin=Admin.new
    end
    def setpass
        @admin=Admin.find(params[:id])
        if @admin.update_attributes(params[:admin])
            flash[:notice]="Your password has updated successfully"
            flash[:color]="valid"
            redirect_to :action => "index" , :controller => 'homes'
        else
            flash[:alert]="Your password could not updated"
            flash[:color]="invalid"
            render 'homes/index'
        end
    end
end

model/admin.rb

class Admin < ActiveRecord::Base
  attr_accessible :email, :password_hash, :password_salt, :picture, :user_name,:password_confirmation,:password, :remember_me
  attr_accessor :password
  attr_accessor :remember_token
  before_save :encrypt_password
  mount_uploader :picture, PictureUploader
  EMAIL_REGEX = /\A[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}\z/i
  validates :email, :presence => true, :uniqueness => true, :format => EMAIL_REGEX
  validates :user_name, :presence => true, :length => {:in => 3..10}
  validates :password, :confirmation => true
 validates_length_of :password, :in => 6..20, :on => :create
 has_secure_password
 def encrypt_password
    if password.present?
      self.password_salt = BCrypt::Engine.generate_salt
      self.password_hash = BCrypt::Engine.hash_secret(password, password_salt)
    end
  end
  def self.authenticate(email, password)
    user = find_by_email(email)
    if user && user.password_hash == BCrypt::Engine.hash_secret(password, user.password_salt)
      user
    else
      nil
    end
  end
   def Admin.digest(string)
    cost = 10
    BCrypt::Password.create(string, cost: cost)
  end

  # Returns a random token.
  def Admin.new_token
    SecureRandom.urlsafe_base64
  end

  # Remembers a user in the database for use in persistent sessions.
  def remember
    self.remember_token = Admin.new_token
    update_attribute(:remember_digest, Admin.digest(remember_token))
  end
  def forget
    update_attribute(:remember_digest, nil)
  end
end

Please help me.