To provide an easy-to-assemble insertion wiring maul or OA maul having an electromagnetic wave shielding performance and an static electricity shielding performance and exhibiting excellent strength.

The wiring maul is made of a thin sheet metal (steel plate) and consists of a body 1 and a cover 5. The body 1 has a bottom plate 2, and inserting side parts 3 and 3 formed on the opposite insides of the bottom plate by bending inward at an angle of 30-60° to form inserting parts 4 and 4 between the bottom plate 2 and the inserting side parts 3 and 3. The cover 5 has an arcuate cross-section in the width direction and it is integrated with the body 1 to form a hollow containing section 7 internally by inserting the opposite end parts 6 and 6 into the inserting parts 4 and 4 slidably in the longitudinal direction.