Patent Literature 1 discloses a clutch engagement control system for engagement and disengagement of transmission of a rotating force between the mainshaft (first shaft) and the countershaft (second shaft). In the clutch engagement control system, for a gear shift and/or the like, the rotational speed of the first shaft and the rotational speed of the second shaft are compared. Then, when the two rotational speeds have become approximately equal, it is determined that the clutch engagement is approximately completed, and then the clutch engagement state is controlled for further transition in order to complete the clutch engagement after the gear shift.