A piston supply apparatus includes a piston gripping portion and a piston supply portion. The piston supply portion includes a connecting rod gripping unit gripping the connecting rod of the piston placed in a preparation area, a guide member abutting against a skirt portion of the piston to match an axial direction of the piston with a predetermined specified direction, a moving unit moving the gripping unit from the preparation area to a supply position in air, and a pivoting unit making the gripping unit pivot such that the piston top portion of the piston in a downward state is set in an upward state. The piston supply apparatus further includes a pressing unit pressing the piston top portion of the piston made to pivot to the upward state against the guide member.