Disclosed herein is a walk-in device for a seat. The walk-in device includes: a rotor configured to operate in conjunction with a recliner during a walk-in operation; a puller configured to operate in conjunction with the rotor during the walk-in operation, and to operate only in conjunction with the recliner without operating in conjunction with the rotor during a folding operation; a rotor spring configured to provide an elastic force to the rotor in a return direction; a puller spring configured to provide an elastic force to the puller in a return direction; and a base plate configured to rotatably install the rotor and the puller on a cushion frame of the seat, wherein the rotor and the puller are configured to set up a single rotation point with respect to the base plate via a hinge shaft.