A service plug is provided with circuit terminals respectively connected to the end of an open electric circuit, a circuit housing provided with the circuit terminals inside and terminal insertion holes, a pair of guide grooves stood on the surface on which the terminal insertions holes are made, guide grooves formed on the respective opposite surfaces of the guide walls, the plug body provided with short-circuiting terminals for short-circuiting the circuit terminals, a lever rotatably coupled to the plug body via a turning shaft which is long in the opposite direction of the guide walls, and bosses which are protruded from both sides of the lever, enter the guide grooves and position the circuit terminals and the short-circuiting terminals.