PURPOSE: To form a good film uniformly on the surface of the band of a wrist watch by ion plating the band consisting of a connecting and brading a large number of cubic pieces, and sticking support means for holding bands and applying voltage tightly on the rear surfaces of the respective cubic pieces.

CONSTITUTION: Rear surfaces 3 of a wrist watch band 1 are wound on circular support means 10, by which respective cubic pieces 2 are stuck tightly to the meaans 10. If voltage is applied to the means 10 in ion plating in this way, the voltage can be applied uniformly upon all the pieces 2. in this state, the means 10 are rotated P' under revolution P with respect to an evaporating source 20, by which good films are formed uniformly only on the surfaces 4 of the watch band.