To facilitate even work in a narrow place by allowing the connection to a machine screw, and allowing operation with one hand when inserting a driver into the machine screw though practically rotating the driver with the other hand after picking and holding the machine screw in an installing position with one hand when fastening a nonmagnetic cross machine screw (having a property of being unattractable by a magnet), and picking and removing the machine screw with the other hand after being loosened up to time just before removal when removing the machine screw.

A slit is formed (only in one direction) toward the root from the tip vicinity in a groove from a tip groove of a cross driver shaft, and a metallic plate a little thinner than a groove width of the slip is inserted, and a side part of the metallic plate tip is projected a little from a groove part of the driver. A projected metallic plate is set in a position for striking on a corresponding part projecting inside a cross groove of the machine screw. When inserting the driver into the screw, the side part on the tip of the metallic plate is strongly strutted against the projecting part of the machine screw, so that a driver shaft and the machine screw are connected.