A valve unit is switchable to an open position at which an outside of an exterior portion and an inner cavity communicate with each other and a closed position at which a communication between the outside of the exterior portion and the inner cavity is blocked in an endoscope. In the endoscope, an electric power is supplied to a drive force generation section only when a connection portion of an universal cord is connected to a peripheral device, and the drive force generation section generates a drive force to drive the valve unit by a supply of the electric power. The valve unit moves from the closed position to the open position by the drive force generated by the drive force generation section.