Abstract: A pair of supply/drain pipes continuous with an actuator are respectively communicable with a pair of oil sumps respectively through an intermediation of a pair of extended paths. The pair of oil sumps is formed in a switch-spool insertion hole and enter a neutral state or a state of being selectively communicated with any one of respective pressure-oil paths and respective oil-return paths. A non-leak valve is provided over respective connection portions and between the pair of supply/drain pipes and the pair of extended paths. The non-leak valve is opened when an operation of a pump is started, is maintained to be opened during the operation of the pump, and is closed when the pump is out of operation.