PURPOSE: To improve the efficiency of a soldering inspection and reliability by forming at least one of a component disposition diagram and a double resist of ink in which substance for discoloring or coloring by heat, ultraviolet ray or electron beam is added as a coloring material.

CONSTITUTION: Since ink for a component disposition diagram 14 and a double resist 15 contains substance for discoloring or coloring by heat, ultraviolet ray or electron beam to be added as a coloring material, it is, for example, black in a normal state, but if it is heated to 35°C or higher, #27 (Fast Black) is discolored to become white by titanium white. Here, the #27 may include, in addition to the Fast Black, green, grown, blue, etc. When the ink is used, since it is black in a normal state, the resist 15 can be distinguished from solder 16 by pattern recognizing by using a monochromatic camera. If the diagram 14 is confirmed, it is heated to 35°C or higher, the diagram 14 thus becomes white, thereby improving its visibility.