A high-friction fluid seal used for high-friction sealing, comprising a fluid seal lip provided on the working fluid filling side to intercept a working fluid; and a dust lip provided on the working fluid non-filling side (the outer side) of the fluid seal lip to intercept dust coming from the outside, wherein the thickness of a working fluid film formed on the extension stroke by the dust lip is smaller than the thickness of a working fluid film formed on the extension stroke by the fluid seal lip.