PURPOSE: To provide adaptability to the alteration of the dimension and shape of a door by mounting a positioning pin, a clamp and an operation rod on a main body plate in a freely detachable manner and providing a lock pin so as to support the same on the operation rod taking a door locking position and the lock releasing position of the door by the revolution of the operation rod.

CONSTITUTION: Two positioning pins 7 are inserted in two engaging holes 33 provided to the upper part of the upper edge of the opening part of a door inner panel and a clamp 5 is inserted in a door from the opening part. At this time, the lower edges of the engaging holes 33 enter the fitting grooves 8 provided to the under surfaces of the positioning pins 7. Subsequently, the clamp 5 is drawn near by a clamp bolt 3 to fix a jig to the door while the contact state of the lower edge 32 of the opening part and a main body plate 1 is kept. For the purpose of the operation due to a robot arm, the operation rod 6 freely detachable through the second revolving shaft 9 vertical to the main body plate 1 and the lock pin 4 supported on the operation rod 6 so as to take a door closing lock position and the lock release position of the door by the revolution of the operation rod 6 are provided.