PURPOSE: To reduce shock at the time of motor start and stop by inserting in series a limit resistance into a motor winding terminal only for a predetermined time at the time of motor start, conducting the low speed start of the motor under an electric current thus limited.

CONSTITUTION: A power seat motor M is provided as a seat slide device drive source, and controlled by the operation of a manual switch 12. At the manual switch 12, a main contact point 12a is connected to either of changeover contact points 12b, 12c by the operation of an operation lever, and motor control relays RL1, RL2 are connected to respective changeover contact points 12b, 12c. Hereupon, a limit resistance R4 is connected in series to a motor M winding terminal between the motor M and a relay connection RL1a. Also, the connection of a changeover means 14 is made in parallel with the limit resistance R4, and the changeover means 14 is constituted with the relay contact point RL3a of a control relay RL3 energized by IC1 for a predetermined time from motor start.