An adjusting device is equipped with a rod and a holder disposed movably in the direction of the length of the rod at an end of the rod, and adjusts the allowance length of the inner cable coupled to the rod and (or) holder. The adjusting device is provided with a lock-discriminating member protruding from the periphery of the holder and a cover covering the periphery of the holder including the lock-discriminating member and the lock. The lock piece does not protrude from the periphery of the holder in the lock state and protrudes to the same height with the lock-discriminating member in the unlock state.