Abstract: A seat sliding apparatus is constructed of a lower rail for mounting to a vehicle floor, an upper rail slidably received on the lower rail, a memory mechanism section, a lock member for locking the upper rail to the lower rail and a walk-in mechanism section for locking and unlocking movement of a vehicle seat in a forward-and-backward direction through operation of the memory mechanism section and the lock member. The memory mechanism section is assembled to at least one substrate so as to a unit.