Sliding device for a vehicle

A sliding device for a vehicle, comprising:

• a first rail;
• a second rail supported relatively movably relative to the first rail in a rail axis direction;
• a lock member received and attached within a section area of one of the first and second rails to extend in the rail axis direction of the one rail for locking the relative movement between the first and second rails, the lock member including a pin;
• a manipulation lever mounted to the lock member for moving the lock member to permit the relative movement between the first and second rails;
• a movement permitting portion formed on at least one of the lock member and the rail attaching the lock member so that the relative movement between the lock member and the rail attaching the lock member in the rail axis direction is allowed with the lock member locking the relative movement, the pin being able to pass through the movement permitting portion;
• and
• a movement restraining portion formed on the rail attaching the lock member to restrain the movement in a lock release direction of the lock member after the relative movement at the movement permitting portion,
• wherein the movement permitting portion includes a first portion with a diameter greater than an outer diameter of the pin and a second portion with a diameter less than the pin.