Abstract: In a front seat of an automobile having a seat back tiltable with respect to the seat cushion, a seat walk-in device, which moves interlockingly with the tilting of the seat cushion, is interposed between a stationary rail fixed on the automobile's floor and a sliding rail fixed under the seat cushion. To provide adequate space for entering or leaving the rear-seat space, the front seat is moved toward the front of the automobile by tilting the seat back forward. On completion of the entering or leaving, the front seat is moved backward after returning the seat back to an upright position. Then, the seat walk-in device automatically locks the front seat in a predetermined position.