A sunroof apparatus includes a supporting bracket configured to support a movable panel, the movable panel opening and closing an opening portion, a guide rail extending in a vehicle front/rear direction, a sliding member connected to the supporting bracket and driven to be movable along the guide rail, a driving member driving the sliding member and causing the movable panel to move upwardly and downwardly and to perform a sliding movement in the vehicle rear direction, a gutter member which extends in the vehicle width direction and is movable along the guide rail and an engaging/disengaging portion provided at the movable panel or at the supporting bracket and being disconnected from the gutter member in a fully-closed state and being connected to the gutter member in a tilt-down state.