PURPOSE: To provide a cylindrical proportional control valve which performs smooth microdrive, improves durability, and reduces size.

CONSTITUTION: A cylindrical proportional control valve comprises a pneumatic cylinder 2 having a piston 8 in which a slide ring 10 having a low friction factor is fitted; and a PMW control solenoid valve which performs opening and closing operation according to a pulse frequency. Further, the proportional control valve comprises a solenoid valve 21 for a feed to feed compressed air from a compressed air feed source to a pressure chamber 15 in the pneumatic cylinder 2; and a control valve having a solenoid valve 22 for discharge to discharge compressed air in the pressure chamber. Moreover, the proportional control valve comprises a control circuit 18 consisting of a deviation means to eliminate an error between an input signal, inputted from the outside to command an arbitrary piston position, and a position signal from a position detecting means 19; and a pulse converting means to convert a deviation signal, outputted by a deviation means, into a pulse signal by means of which the control valve is driven.