A stroke start position is detected by a change amount of a clutch hydraulic pressure that has become smaller than a negative predetermined value ΔP1 during clutch connection control by a clutch actuator, and a stroke end position is detected by a change amount of the clutch hydraulic pressure that has become larger than a positive change amount ΔP2. By using a proportional function formed by a stroke start hydraulic pressure Ps detected at the stroke start position and a stroke end hydraulic pressure Pe detected at the stroke end position, a target half-clutch hydraulic pressure Ph that generates a predetermined target half-clutch capacity in a predetermined half-clutch state between the stroke start position and the stroke end position is calculated. By using the target half-clutch hydraulic pressure Ph, a clutch control amount in the predetermined half-clutch state is determined.