A rotary valve includes: a valve chamber in which at least three ports including at least a first port, a second port, and a third port are disposed in a circumferential direction; at least three external flow paths communicating with the three ports, respectively; and a valve rotor accommodated in the valve chamber so as to be rotatable and configured to switch a flow of a fluid between the ports by a rotation operation. The first port extends in the circumferential direction of a wall portion of the valve chamber. A first buffer portion is formed between the first port and the external flow path corresponding to the first port. The first buffer portion covers the entire first port and serves as a space having a circumferential width larger than a circumferential width of a valve flow path.