A grease discharge device includes a motor, a plunger, a grease supply unit, a pump, a check valve, and a relief valve. The plunger reciprocates by driving of the motor. The grease supply unit supplies grease to a forward movement side with respect to a backward movement side dead center of the plunger. The pump performs a discharge behavior of the grease by the reciprocation of the plunger. The check valve is disposed at a downstream side with respect to a forward movement side dead center of the plunger in a discharge path of the grease inside the pump. The relief valve is disposed between a supply portion of the grease by the grease supply unit and the check valve. The relief valve releases the grease inside the discharge path to the grease supply unit side according to a pressure rise inside the discharge path.