To quicken a cooling velocity of a friction face so as to stabilize a structure, and join even a material of easy-to-oxidize member without generating the strong oxidation reaction by covering opposing faces of two members, at least one of which is rotated, with liquid.

Overlaying can be performed by using a cladding material as one of members. The liquid used for this device comprises water, and the non-heating property liquid with soft viscosity such as oil and the like at a seawater area. The cladding material 3 is pressurized and pressed to a base material 2 while a rotation means 30 and a rotation displacement prevention means 40 are inserted and the tip of the cladding material 3 is abutted to the surface of the base material 2 provided to a worktable 50 having a XY direction driving device 51, so that the base material 2 and the tip part of the cladding material 3 are fully dipped in the water 61 inside a vessel 60. Then, when a pulley 32 is rotated at high velocity, the cladding material 3 is softened by the friction heat so as to form a cladded layer 6 on the surface of the base material 2. Further, it may be possible to overlay the butt portion of two base materials covered with the liquid.