In the relief valve, an annular convex portion 16a that is convexed in a direction in which a valve element 5a moves away from a valve hole 17 along a center axis of the valve hole 17 and that is arranged around the valve hole 17 is formed in a valve chamber 16, an annular concave portion 5d that is concaved in the direction in which the valve element 5a moves away from the valve hole 17 is formed in the valve element 5a, and in a shut-off state, the annular convex portion 16a is accommodated in the annular concave portion 5d, and an annular channel 19 that extends in a direction of the center axis is formed between an outer peripheral surface 16b of the annular convex portion 16a and an inner peripheral surface 5e of the annular concave portion 5d.