When a count value concerning with the travel of the vehicle in a two-wheel drive state reaches or exceeds a predetermined value, the state of drive in a transfer is temporarily switched to a four-wheel drive state by connecting a synchromesh mechanism while keeping a mesh clutch disconnected, so that rotary members that do not rotate during the two-wheel drive state, such as a second output shaft, are temporarily rotated. Thus, the rotary members are restrained from remaining in contact at fixed portions and therefore being partially worn. Besides, there is no need to provide a mechanism for temporarily rotating the rotary members, such as the second output shaft, separately from the synchromesh mechanism that is normally provided for the four-wheel drive travel in the related art. Therefore, it is possible to improve durability without involving cost increase, space efficiency deterioration, etc.