A sliding assisting apparatus assists a movable body to move between a drawn-out position and a drawn-in position. The apparatus includes a unit main body to be attached to a main body or the movable body, and a pair of strikers to be attached to the main body or movable body. The unit main body includes a pair of sliders slidably disposed inside a case, lock members movably supported on the respective sliders, coupling parts provided on the case for engaging the lock members, and an urging device provided between the sliders for accumulating a force when the sliders slide away from the other. One striker switches one slider between a case restrained position in which one coupling part engages one lock member and a case restraint released position in which the one coupling part releases the one lock member.