an oil seal is disclosed in which an axially extending annular portion is formed at a radially inward edge of either one of a support member and a sealing member . an annular elastic sealing member extends from a free end of the axially extending portion in a radially inward direction and in an axial direction opposite to the extending direction of the axially extending portion , thus forming a sealing portion for sealing an outer circumferential surface of the rotary shaft .