PROBLEM TO BE SOLVED: To provide a selector valve capable of improving the supply/discharge speed of air supplied to an airtight chamber, and a telescopic unit and a propulsion device using the selector valve.SOLUTION: A selector valve includes: a first flow passage in which pressurized fluid flows； a valve body provided so as to be freely moved by being pressed by the fluid flowing in the first flow passage； energization means of energizing the valve body so as to antagonize pressing force that the fluid flowing in the first flow passage presses the valve body； a second flow passage in which the fluid flowing in the first flow passage flows when the pressing force of fluid acting on the valve body is stronger than energization force of the energization means； and a third flow passage that communicates with the second flow passage when the energization force of the energization force acting on the valve body is stronger than the pressing force of the fluid flowing in the first passage.SELECTED DRAWING: Figure 5
