Abstract: Miniature electric light bulb sets for decorative illumination are prepared by branching out two electric wires from one attachment plug and further branching out each of said two electric wires into two further electric wires at respective branch plates and providing a group of miniature electric light bulbs grouped at each terminal of the respective branched wires, the improved miniature electric light bulb sets for decorative illumination being prepared by simplifying each component, and reducing the production costs while maintaining safety.