To provide a channel switching valve for switching channels only by one drive means, miniaturizing a valve structure, and reducing manufacturing costs.

The channel switching valve selectively switches a first channel A reaching a second port 2 from a first port 1, and a second channel B reaching a third port 3 from the first port 1 by projecting the first port 1 in the middle of a body pipe section 4, and projecting the second and third ports 2, 3 at both the sides. An operation rod 6 reciprocating in an axial direction is arranged inside the body pipe section 4, a pair of diaphragms 8, 8 for constantly blocking both the end sections of the body pipe section 4 are provided at both the end sections of the operation rod 6, and a pair of valve elements 7A, 7B for closing the first channel A in the forward motion of the operation rod 6, opening the second channel B, and opening the first channel A in the backward motion and closing the second channel B are provided adjacently inside both the diaphragms 8, 8.