A roof apparatus for a vehicle, comprising: a guide member arranged on a guide rail and sliding therealong in a longitudinal direction of the vehicle, the guide rail adapted to be mounted at a side edge of an opening portion formed in a roof portion of the vehicle; a support member engaged with the guide member and supporting a movable panel opening and closing the opening portion; a drive member driving the movable panel supported by the support member, the drive member moving the guide member rearward in the longitudinal direction so that the movable panel tilts up and opens remaining in a tilted-up state; a first garnish supported by the guide rail and covering a clearance between the support member and the guide rail from an interior space of the vehicle when the movable panel is in the tilt-up operation and in the opening operation; and a second garnish supported by the movable panel and covering the support member from the interior space of the vehicle, the second garnish covering the guide member when the movable panel is in a fully closed state and in the tilt-up operation; characterised in that it further comprises: a third garnish connected to the guide member or the support member and slidably supported thereby along the guide rail in the longitudinal direction, the third garnish covering an opening portion defined between the first garnish and the second garnish, from the interior space of the vehicle when the movable panel is in the tilt-up operation, in the fully closed state, and in the opening operation. a guide member arranged on a guide rail and sliding therealong in a longitudinal direction of the vehicle, the guide rail adapted to be mounted at a side edge of an opening portion formed in a roof portion of the vehicle; a support member engaged with the guide member and supporting a movable panel opening and closing the opening portion; a drive member driving the movable panel supported by the support member, the drive member moving the guide member rearward in the longitudinal direction so that the movable panel tilts up and opens remaining in a tilted-up state; a first garnish supported by the guide rail and covering a clearance between the support member and the guide rail from an interior space of the vehicle when the movable panel is in the tilt-up operation and in the opening operation; and a second garnish supported by the movable panel and covering the support member from the interior space of the vehicle, the second garnish covering the guide member when the movable panel is in a fully closed state and in the tilt-up operation; characterised in that it further comprises: a third garnish connected to the guide member or the support member and slidably supported thereby along the guide rail in the longitudinal direction, the third garnish covering an opening portion defined between the first garnish and the second garnish, from the interior space of the vehicle when the movable panel is in the tilt-up operation, in the fully closed state, and in the opening operation. a third garnish connected to the guide member or the support member and slidably supported thereby along the guide rail in the longitudinal direction, the third garnish covering an opening portion defined between the first garnish and the second garnish, from the interior space of the vehicle when the movable panel is in the tilt-up operation, in the fully closed state, and in the opening operation.