An image forming apparatus includes an image carrying member, a transfer device, cleaning devices, and a waste toner collecting unit. The cleaning devices collect toner remaining on the image carrying member and toner remaining in the transfer device as waste toner after a toner image is transferred by the transfer device from the image carrying member to a recording medium. The waste toner collecting unit includes a container storing the waste toner, a conveying device provided in the container, and a detection unit provided above a position where the waste toner is pressed and up-thrust by the conveying device. The conveying device horizontally conveys the waste toner, and presses and up-thrusts the waste toner after an amount of the waste toner reaches a predetermined value. The detection unit is pressed and displaced by the pressed and up-thrust waste toner, and detected by a sensor.