Intended is to provide a fluid machine that can prevent wear of a rotation preventing pin. The fluid machine includes a housing, a fixed scroll fixed with respect to the housing, a turning scroll that revolves around the fixed scroll, and a rotation preventing mechanism that prevents the rotation of the turning scroll. The rotation preventing mechanism includes a rotation preventing pin projected from a wall surface at the housing side or the turning scroll side, and a restraining member that restricts the position of the rotation preventing pin by engaging with the rotation preventing pin. A projecting side end of the rotation preventing pin has a taper shape, and the end of the taper shape has an R-shape.