PURPOSE: To meet various kinds by enabling to carry out and in the type welding jig to a lifter device having lifter blocks to move vertically by cylinders.

CONSTITUTION: The welding jig 10 is provided on a pedestal 18 provided with casters 19 to form the truck type welding jig. The truck type welding jig 10 is arranged so as to be carried out and in to the lifter device 20 having the lifter blocks 11 to move vertically by the cylinders 12. The lifter blocks 11 are provided movably vertically on both sides of the pedestal 18. The lifter blocks 1 are provided with welding jig clampers 13, lifter positioning blocks 14, welding jig positioning blocks 15 and welding jig positioning knock holes 16. The truck type welding jig 10 is fixed on the lifter device 20 and the truck type welding jig is then fixed on the fixed position by actions of the cylinders 12. Consequently, the jig setup can be carried out easily and quickly only by lifting up or down the welding jig.