SLIDING DEVICE

Provided is a sliding device which can avoid unintended locking release without depending on an excessive engagement force of an engagement member. The sliding device (1) includes a lock mechanism (20) that locks an upper rail (3) to a lower rail (2). The lock mechanism (20) includes: an engagement member (5) that shifts in the upper rail between a locking position and a release position; a first urging member (11) that gives an urging force to the engagement member (5) in a direction from the release position to the locking position; and an operation member (7) for shifting the engagement member (5) from the locking position to the release position. The operation member (7) comprises a shift restrictor (7c) that keeps the engagement member (5) from shifting to the release position when the engagement member (5) is in the locking position.