A rotary valve which can securely shut off a fluid flow without improving a working accuracy of an outer peripheral surface of a valve and an inner diameter portion of a body, and which has a simple and compact structure, wherein a gap is formed between the outer peripheral surface of the valve and the inner diameter portion of the body, a lip portion of seal means attached within a second lead air flow path is brought into contact with the outer peripheral surface of the valve on the basis of an elastic force of a support portion, and the lip portion securely seals between the second lead air flow path and the gap.