To provide an electromagnetic direction change-over valve provided between two-system transmission closed circuits for driving left and right wheels of one vehicle to realize with one unit three modes of differential mode, differential lock mode and unload mode and save electric power consumption in the normal traveling.

An electromagnetic direction change-over valve 30 has 4-port 3 positions. When the electromagnetic direction change-over valve 30 is in the neutral position of 3 positions, two flow paths are formed which afford communication between the first port P1 and the third port P3 of the 4 ports and between the second port P2 and the fourth port P4 respectively. Also, when the valve 30 is in one offset position (a), the respective ports P1, P2, P3, P4 are closed. Also, when the valve 30 is in the other offset position (b), two flow paths are formed which allow the first port P1 to communicate to the fourth port P4 and the second port P2 to communicate to the third port P3 respectively.