A release bearing comprising: an outer ring having an outer ring raceway formed on an inner periphery thereof, an inner ring having an inner ring raceway formed on an outer periphery thereof, a plurality of rolling elements provided to be freely rollable between the outer ring raceway and the inner ring raceway, and a pair of seal rings (20, 9b) of which outer peripheral edge portions are respectively to be engaged to inner peripheries of both axial end portions of the outer ring, the seal rings (20, 9b) being configured to close openings at both axial ends of a space which exists between the inner periphery of the outer ring and the outer periphery of the inner ring and in which the rolling elements are provided, wherein an inner diameter-side end portion of one of the pair of seal rings is provided with a contact lip of which a tip edge is sliding-contacted to an axial end surface of the inner ring over an entire circumference and a non-contact lip of which a tip edge is arranged to closely face an outer periphery of an axial end portion of the inner ring over an entire circumference, characterized in that an inner peripheral edge portion of the one seal ring is provided with a radial non-contact lip extending radially inward from an inner peripheral edge portion of the contact lip and having a tip edge positioned at a more radially inner side than an inner periphery of the axial end portion of the inner ring, and a labyrinth seal is formed between the axial end surface of the inner ring and an axial side surface of the radial non-contact lip, radially inward from a sliding contact part between the tip edge of the contact lip and the axial end surface of the inner ring. an outer ring having an outer ring raceway formed on an inner periphery thereof, an inner ring having an inner ring raceway formed on an outer periphery thereof, a plurality of rolling elements provided to be freely rollable between the outer ring raceway and the inner ring raceway, and a pair of seal rings (20, 9b) of which outer peripheral edge portions are respectively to be engaged to inner peripheries of both axial end portions of the outer ring, the seal rings (20, 9b) being configured to close openings at both axial ends of a space which exists between the inner periphery of the outer ring and the outer periphery of the inner ring and in which the rolling elements are provided, wherein an inner diameter-side end portion of one of the pair of seal rings is provided with a contact lip of which a tip edge is sliding-contacted to an axial end surface of the inner ring over an entire circumference and a non-contact lip of which a tip edge is arranged to closely face an outer periphery of an axial end portion of the inner ring over an entire circumference, characterized in that an inner peripheral edge portion of the one seal ring is provided with a radial non-contact lip extending radially inward from an inner peripheral edge portion of the contact lip and having a tip edge positioned at a more radially inner side than an inner periphery of the axial end portion of the inner ring, and a labyrinth seal is formed between the axial end surface of the inner ring and an axial side surface of the radial non-contact lip, radially inward from a sliding contact part between the tip edge of the contact lip and the axial end surface of the inner ring.