To provide an image forming apparatus that keeps the proper amount of toner in a developing unit to prevent toner to be oversupplied in supplying toner by toner remaining amount detection.

An image forming apparatus comprises a detection times counter that counts the number of times that a toner remaining amount detection sensor 18d detects that toner accommodated in a developing unit 18 is not less than the predetermined amount for every predetermined period. When the count value of the detection times counter is not more than the predetermined value, the image forming apparatus supplies toner from a sub-hopper 17 to the developing unit 18; and when the count value of the detection times counter begins to increase, stops supplying toner from the sub-hopper 17 to the developing unit 18.