A parallel operation control method for different type power generation apparatuses to shift the power generation apparatuses having respective different drooping characteristics, in which the drooping characteristic is defined as a characteristic of decrease of a rated frequency along with an increase of a load, from independent operation of the power generation apparatuses under suitable drooping characteristics to parallel operation thereof to drive a common drive target, includes determining a load of one of the power generation apparatuses by subtracting a load of the other of the power generation apparatuses from a predetermined required load; changing a drooping characteristic of the one of the power generation apparatuses so as to coincide with a drooping characteristic of the other of the power generation apparatuses; and controlling the one of the power generation apparatuses so as to maintain frequency at the time of changing the drooping characteristic.