A slide rail device includes forward/rearward-movement restricting grooves formed on an upper rail; lock portions which are movable in the forward and/or rearward direction relative to the upper rail, wherein the lock portions are lock-engaged with the lock grooves and the forward/rearward-movement restricting grooves when the lock release lever is positioned at the locked position, and the lock portions are released from the lock grooves when the lock release lever is positioned at the unlocked position; and restricting lugs formed on an upper rail, wherein the restricting lugs restrict the lock portions from moving forward or rearward from the forward/rearward-movement restricting grooves, to which the lock portions correspond, by the lock portions coming in contact with the restricting lugs when the lock release lever is positioned at the unlocked position.