A pump unit installed inside a wing includes a backup hydraulic pump that can supply pressure oil to an actuator when a loss or reduction occurs in the function of an aircraft central hydraulic power source and an electric motor that drives the pump. A wing structure portion forming the surface structure of the wing is provided with an inlet port and an exhaust port that are formed therethrough. The inlet port is provided so as to be opened and closed by an inlet port opening/closing portion, and the exhaust port is provided so as to be opened and closed by an exhaust port opening/closing portion.