In an outer slide type sunroof unit, a first seal member is mounted to a side edge of a molded part provided on an outer peripheral edge of a fixed rear panel; a second seal member is mounted to a rear edge of the molded part and has a lateral end facing forward at a position offset outward relative to a rear end of the first seal member; and a third seal member is provided on an outboard side of the first seal member. The third seal member includes a first portion for resiliently contacting an inner edge of a roof opening and a second portion that resiliently contacts the first seal member and cooperates with the first seal member to define a passage for a stay supporting a slidable front panel, a rear end of the first portion being bonded to the lateral end of the second seal member.