Is the `@count` an instance variable or class variable in Ruby?

class Counter
   def self.counted_new
      @count = 0 if @count.nil?
      @count += 1
      new
   end

   def self.count
      @count
   end
end

In format, @count looks like a instance variable, but when I load this in "irb"(interface ruby) and type four command code

Counter.counted_new
Counter.count
Counter.counted_new
Counter.count

@count finally became 2! acting like a class variable