A relief device includes a relief housing constituted by a relief inflow portion, a valve passage portion, a recess, and an oil discharge portion having a relief hole; a relief valve having a small-diameter portion between a first large-diameter portion and a second large-diameter portion; and a spring elastically biasing the relief valve toward the relief inflow portion. The recess is formed at a position that is closer to the relief inflow portion side than to the oil discharge portion, the axial length of the recess is larger than the axial length of the first large-diameter portion of the relief valve, and the shortest axial distance between the recess and the relief hole is less than the axial length of the small-diameter portion.