At an electrical work site, workers face the threat of electric shock. It is possible to prevent accidents from occurring by wearing electrically nonconductive clothes and using tools covered with an insulating layer as measures against electric shocks. However, tools covered by rubber or resin to block electricity are hard to use at work site, which leads to stress for workers. Now we propose Slim Insulation Screwdrivers, which prevent electric shock, but do not decrease work performance. These products successfully keep the shaft diameter small without losing the insulation function, as a screwdriver shaft with an insulating layer normally tends to be bigger. There is good visibility of the tip for work in narrow places and easy access to a screw in secluded spots, and they are very easy to use. We have developed them with the aim of both the safety of workers and the primary usability of tools.