To reduce disconnection when an extension cord is entangled with an obstacle and a burden imposed on an operator arm due to weight by forming a driver body, a rechargeable battery and a cord in a pair, and performing stable work by making a driver freely portable.

This portable driver can freely act while attaching a rechargeable battery to a belt by holding a driver body A by a dominant arm on the basis of the work content regardless of internal facing and external facing. In a screw driver A, a connecting cord is connected to a cord inserting port 1 of the driver body A, and a rechargeable battery is also connected. Work can be kept stable by dispersing weight by installing this rechargeable battery on a belt. A laser AR can fasten a machine screw by applying a laser along a backing from above a plaster board, and a using effect is constantly economical.