To easily install a discharge passage in a similar way to a suction passage in an oil passage structure of an electric oil pump provided separately from an engine-driven pump.

The discharge passage 14 for the electric oil pump is formed integrally with an oil pan 7 and connected to a port 18 of a control valve 9 via a connection member 15, and the connection member 15 is held between an oil pan mounting wall portion 2a and the control valve 9. An oil passage end 16a of the connection member 15 distant from the control valve 9 is opened in an oil pan mounting direction so that the discharge passage 14 is automatically connected to the oil passage end 16a of the connection member 15 when the oil pan 7 is mounted. The oil passage end 16b of the connection member 15 close to the control valve 9 is opened to the direction of separation from the oil pan mounting wall portion 2a of a transmission case 2 and connected to a corresponding port 18 of the control valve 6 via an elastic pipe 19 inserted there between.