PURPOSE: To give a comfortable and slight push feeling to the driving operation by setting the judging condition on the basis of a specified expression and connecting jaw clutches when the input shaft speed is equal to or slightly greater than the synchronous speed.

CONSTITUTION: A transmission is provided with an input shaft 16 to be connected to a motor E by a non-engagement coupling C, and a mechanical transmission 11 having a pair of jaw engagement members corresponding to a plurality of gear ratios. In controlling of the transmission, a command signal to be fed to an actuator 29 of connecting/disconnecting a pair of jaw members is found on the basis of signals indicative of the input shaft and output shaft rotational speeds IS, OS, by a CPU 31. When an expression (OS, GRt)+ K≥ISe≥(OS.GRt) is held, the connection of a pair of jaw members is started. In the expression, K indicates the positive rotational speed, and ISe indicates the estimated input shaft speed in initial connection of a pair of jaw members corresponding to the target gear ratio.