A belt type continuously variable transmission includes a primary pulley (11), a secondary pulley (12), a belt (13) wound around the primary pulley and secondary pulley; a sensor (27, 21) for detecting a vehicle running state; and a controller (1). The controller (1) is programmed to: set a final pulley ratio achieved by a shift of the pulley ratio of the primary and secondary pulleys, based on the vehicle running state, compute a primary steady oil pressure supplied to the primary pulley and a secondary steady oil pressure supplied to the secondary pulley based on an input torque inputted to the primary pulley and an actual pulley ratio, determine a target shift speed based on the final pulley ratio, compute a target stroke speed of the primary pulley and/or secondary pulley from the target shift speed, compute a target pulley rotation speed of the primary pulley, based on the vehicle running state, compute a transitional oil pressure correction amount which can attain the target shift speed, in response to the target pulley rotation speed and the target stroke speed, and set one of the oil pressure supplied to the primary pulley and the oil pressure supplied to the secondary pulley, to the sum of the steady oil pressure and the transitional oil pressure correction amount, so as to attain the final pulley ratio.