To provide a force feed device for lowering the height of a built-in object, and installable and usable on a floor by being installed on a wall draining type flush toilet bowl different in the drain port height.

This force feed device is composed of a body vessel for storing a waste material-waste water from an inflow port, and a force feed part provided in the body vessel, and forcibly feeding the waste material-waste water outside from a delivery port of the body vessel by rotary motion of a rotary shaft, and has the rotary shaft almost horizontally arranged to a bottom surface of the body vessel so that the height of the built-in object of the device can be lowered, and a device body can be formed as a compact device in the height direction.