Abstract: The powder container includes a powder discharging outlet at one end portion of one side wall of the powder container. The powder replenishing device further includes a reciprocating motion device that reciprocates the powder container between forward and backward directions with respect to a moving direction of the powder toward the powder discharging outlet so as to move the powder in the powder container toward the powder discharging outlet in a state that the powder discharging outlet is directed downward in substantially a vertical direction.