PURPOSE: To prevent the edge of a printed circuit board from chipping off when a connection part to be connected to a base material is cut.

CONSTITUTION: Rinforcing copper foils 52, 53, 54 and 55 for enhancing the strength of the connection parts 43, 44, 45 and 46 are formed near the connection parts 43-46 formed at the edge part of the printed circuit board 32 and connected to the base material to which parts are attached. When the board 32 is cut from the base material, the edge part thereof does not chip off because the strength of the coupling parts 43-46 is enhanced. Also, the foils 52-55 can be formed inexpensively only by slighly changing the pattern of a stroboscopic circuit.