FOUR-WHEEL-DRIVE VEHICLE

Provided is a clutch control system for a four-wheel drive vehicle, the system allows a prompt switching from a two-wheel drive traveling to a four-wheel drive traveling. A clutch control system includes: a dog clutch (8) that separates a rear wheel drive system from a front wheel drive system by releasing the dog clutch; an electronically controlled coupling (16) that distributes the driving force of a transverse engine (1) to left and right rear wheels (19, 20) in accordance with a clutch connection capacity; and a 4WD control unit (34) that switches the drive mode to one of a disconnect two-wheel drive mode with the dog clutch (8) and the electronically controlled coupling (16) released, a connect four-wheel drive mode with the dog clutch (8) and the electronically controlled coupling (16) connected, and a stand-by two-wheel drive mode with the dog clutch (8) connected while the electronically controlled coupling (16) released.