A vehicle power transmission system includes: a transmission; a shift actuator; a clutch; a clutch actuator for mutually switching between the transmission and the shutting off of a driving force at the clutch; and a control device being configured to, when having detected that the vehicle is in the travelling state and that the clutch actuator is abnormal by use of the travelling state detection sensor and the CA abnormality detection sensor, control the operation of the shift actuator and cause the selected gear stage in the transmission to be shifted into neutral before the vehicle comes to a stop while shifting the selected gear stage in the transmission into a gear stage having a lower gear ratio.