PURPOSE: To illuminate the working place and its vicinity before a machining tip tool without generating the shadow by the tool by fitting a small annular lamp to the tip part of a base body in the condition where the machining tip tool such as a bit or a drill of a rotary tool is inserted in a void at the center part of the small annular lamp.

CONSTITUTION: A plug 10' of a mouth piece which is commonly used as the plug is inserted in a receptacle at the tip part of a base body 1 in the condition where a machining tip tool 6 and a chuck 5 are inserted in a void at a center part of a small annular lamp 9, this plug 10' is electrically connected to an electrical contact terminal 12 of the receptacle. This small annular lamp 9 is connected to a power supply by an electric circuit through an illumination switch 11. When this illumination switch 11 is turned on, the current flows from the power supply through the electric circuit, and the small annular lamp 9 fitted to the tip part of the base body of the rotary tool is lit, and illuminates the machining place and its vicinity before the tool through the transparent tip material 15 where the machining tip tool 6 is passed through.