A walk-in seat is provided, which has decreased number of components, and has a vacant space formed below a seat cushion so that the walk-in seat may be used even for a different-level seat track. The walk-in seat has a first control lever 171 for unlocking a first locking mechanism 100; a second control lever 181 for unlocking a second locking mechanism 100′; a memory mechanism 300 holding the first control lever 171 such that when a first upper rail 5 is located between a middle position and a foremost position with a seatback being tilted most forward, the first locking mechanism 100 is unlocked; first cable means FC operating such that when the seatback of a seat is tilted to a most forward position, the means FC drives the first control lever 171 to unlock the first locking mechanism 100; and second cable means SC transmitting operation of the first control lever 171 to the second control lever 181.