An automatic seatbelt system which has a flexible tape extending continuously along a vehicle body form a roof side portion through a center pillar to a door so as to move a shoulder webbing connected to the roof side portion and a lab webbing connected to the door at the same time by a single driving sprocket wheel in response to an occupant entering or leaving a vehicle. The tape has a plurality of openings along the longitudinal direction thereof and the sprocket wheel is meshed with the tape by the openings. A shoulder guide rail is provided along the roof side portion of the vehicle body, within which a shoulder guide member guiding the shoulder webbing and connected to the trape is slidably received. A lap guide rail is provided along the door, within which a lap guide member guiding the lap webbing and connected to the tape is slidably received. When the sprocket wheel rotates, both shoulder and lap seatbelt webbings are simultaneously moved through the tape toward either the front side of the vehicle to provide an enough space for the occupant to enter the vehicle, or the rear side of the vehicle to place the webbings over the occupant at a seat.