To provide an oil seal configured so that the sealing ability of the oil seal is improved by preventing muddy water from accumulating on an upper part of a dust lip disposed at a machine-exterior side.

The oil seal is provided with a second seal member at a machine-exterior side of a first seal member, the first seal member having a fixed section to a housing, a main lip, and a first dust lip. The second seal member integrally has: an end surface covering section for covering an end surface of the housing; an outer peripheral engagement section fitted over the outer peripheral surface of the housing from one side in the axial direction and engaged with a stepped engagement section provided on the outer peripheral surface of the housing to retain the second seal member at the housing; an inner peripheral engagement section fitted to the inner peripheral surface of the shaft hole in the housing from the one side in the axial direction; and a second dust lip in close contact with a shaft at the machine-exterior side of the first seal member.