To eliminate a problem that an actuator moves due to a leakage of a small amount of pressure oil when this valve is shut off by providing a restriction passage communicating a second port with drain when a poppet valve element is displaced in the direction of seating on a seat opening and the poppet valve body is seated on the seat opening to shut off the communication between ports.

A passage opening and closing valve is constituted in such a way that, when total force of pressure on one side of a first port 1 and a second port 2 or pressure of both ports is larger than a set force by a spring 6, a poppet valve element 4 having a first pressure receive area part A subjected to the action of pressure oil in the first port 1 and a second pressure receive area part B (>A) subjected to the action of pressure oil in the second port 2 moves upward to open a passage so that a flow of pressure oil between both ports 1 and 2 becomes possible. When this passage opening and closing valve is shut off, the second port 2 communicates with a drain port 7 side through a restriction passage 14 formed on the valve element 4. Consequently, it is possible to exclude a leakage on a drain side even if a leakage from the primary side to the secondary side occurs and prevent unintentional operation of an actuator securely.