A method of controlling a hybrid vehicle including an engine, a motor, a friction engagement element provided between the engine and the motor to be capable of being engaged and/or disengaged by hydraulic pressure, and a hydraulic control circuit configured to control the hydraulic pressure to be applied to the friction engagement element, the method comprising the steps of: controlling the hydraulic pressure to be applied to the friction engagement element in response to a startup demand of the engine in a stopped state during traveling of the hybrid vehicle so that the friction engagement element is shifted from a released or disengaged state to one of a given slipping state and an engaged state; and controlling the motor and the engine so that the motor cranks the engine to start, one or both of during and after the controlling the hydraulic pressure, the method being characterized by controlling the hydraulic pressure as follows: when a target driving force of the hybrid vehicle is below a given value, setting an instruction hydraulic pressure for the hydraulic control circuit to a first hydraulic pressure and maintaining the first hydraulic pressure for a given period of time, then setting the instruction hydraulic pressure to a second hydraulic pressure and maintaining the second hydraulic pressure until the engine start is completed, and then setting the instruction hydraulic pressure to a third hydraulic pressure, the first hydraulic pressure being a pressure at which an increase rate in an engagement pressure at a start of engaging of the friction engagement element becomes below a given rate, the second hydraulic pressure being a pressure at which an engine-startup engagement pressure to transmit torque required for the engine start is applied to the friction engagement element, and the third hydraulic pressure being a pressure to set the friction engagement element to the engaged state; and when the target driving force of the hybrid vehicle is above the given value, setting the instruction hydraulic pressure to the second hydraulic pressure without setting to the first hydraulic pressure, and maintaining the second hydraulic pressure until the engine start is completed, and then setting the instruction hydraulic pressure to the third hydraulic pressure. controlling the hydraulic pressure to be applied to the friction engagement element in response to a startup demand of the engine in a stopped state during traveling of the hybrid vehicle so that the friction engagement element is shifted from a released or disengaged state to one of a given slipping state and an engaged state; and controlling the motor and the engine so that the motor cranks the engine to start, one or both of during and after the controlling the hydraulic pressure, the method being characterized by controlling the hydraulic pressure as follows: when a target driving force of the hybrid vehicle is below a given value, setting an instruction hydraulic pressure for the hydraulic control circuit to a first hydraulic pressure and maintaining the first hydraulic pressure for a given period of time, then setting the instruction hydraulic pressure to a second hydraulic pressure and maintaining the second hydraulic pressure until the engine start is completed, and then setting the instruction hydraulic pressure to a third hydraulic pressure, the first hydraulic pressure being a pressure at which an increase rate in an engagement pressure at a start of engaging of the friction engagement element becomes below a given rate, the second hydraulic pressure being a pressure at which an engine-startup engagement pressure to transmit torque required for the engine start is applied to the friction engagement element, and the third hydraulic pressure being a pressure to set the friction engagement element to the engaged state; and when the target driving force of the hybrid vehicle is above the given value, setting the instruction hydraulic pressure to the second hydraulic pressure without setting to the first hydraulic pressure, and maintaining the second hydraulic pressure until the engine start is completed, and then setting the instruction hydraulic pressure to the third hydraulic pressure. when a target driving force of the hybrid vehicle is below a given value, setting an instruction hydraulic pressure for the hydraulic control circuit to a first hydraulic pressure and maintaining the first hydraulic pressure for a given period of time, then setting the instruction hydraulic pressure to a second hydraulic pressure and maintaining the second hydraulic pressure until the engine start is completed, and then setting the instruction hydraulic pressure to a third hydraulic pressure, the first hydraulic pressure being a pressure at which an increase rate in an engagement pressure at a start of engaging of the friction engagement element becomes below a given rate, the second hydraulic pressure being a pressure at which an engine-startup engagement pressure to transmit torque required for the engine start is applied to the friction engagement element, and the third hydraulic pressure being a pressure to set the friction engagement element to the engaged state; and when the target driving force of the hybrid vehicle is above the given value, setting the instruction hydraulic pressure to the second hydraulic pressure without setting to the first hydraulic pressure, and maintaining the second hydraulic pressure until the engine start is completed, and then setting the instruction hydraulic pressure to the third hydraulic pressure.