The invention provides a composite valve which can achieve both an improvement of a flow
rate control precision in a small flow rate region and an increase of a controllable flow rate (a reduction of a pressure loss), and can enhance a sealing performance of a
pilot passage by a
pilot valve body, whereby it is possible to securely prevent a malfunction and it is possible to enhance a reliability. When a lift amount of a second valve body (24) for a small flow
rate control is equal to or less than a predetermined amount (Tc), a
pilot passage (19) is closed by a
pilot valve body (60) which is slidable on an inner wall of a bush retention body (28), and a first
valve port (13) is closed by a first valve body (15) for a large flow
rate control, thereby taking a small flow rate control state in which a flow rate is controlled in correspondence to a lift amount of the second valve body (24). When the lift amount of the second valve body (24) goes beyond the predetermined amount (Tc), a
pilot valve body (20) is raised in correspondence to a rising motion of a valve shaft (25) so as to open the pilot passage (19), thereby taking a large flow rate control state in which the first valve body (15) opens the first
valve port (13). The
pilot valve body (60) is outward inserted slidably to the valve shaft (25), and is energized downward by a spring member (26) so as to close the pilot passage (19). Further, when the lift amount of the second valve body (24) is increased more than the predetermined amount Tc, the pilot valve body (60) is caught on the valve shaft (25) so as to be pulled up.