To reduce the number of part items by integrally forming a spring piece and a valve element.

This check valve is constituted by rotatably incorporating the valve element 12 for opening and closing a fluid passage 7 into a housing 6. The valve element 12 is composed of a pair of valve plates formed in half-disk shapes. A rotary shaft 13 is provided on one valve plate 12A, and a bearing ring 18 is provided on the other valve plate 12B. The whole valve element 12 is integrally formed in a state of combining these valve plates 12A and 12B. The spring piece 22 is and integrally formed obliquely outward on the valve plates 12A and 12B, respectively, so as to oppose each other. When combining both the valve plates 12A and 12B, tips of the spring piece 22 are brought into abutting states. When fuel is supplied from the upstream side of the valve plates, the spring piece 22 is displaced accompanied by the rotational movement of the valve plates in the opening direction, and a spring force is energized for energizing both the valve plates 12A and 12B in the closing direction.