PURPOSE: To eliminate the danger of an electric shock, and to generate no contact failure by placing the primary side of a transformer on a body part, and separating the secondary side to an illuminating part which is attachable and detachable, from the body part.

CONSTITUTION: The secondary side transformer part 20a of an illuminating transformer, and the primary side transformer part 20b are attached in advance to an illuminating part 1 and a body part 2 of an illuminating device, respectively, and when the illuminating part 1 is inserted into the body part 2, the primary and the secondary side transformer parts 20a, 20b approach each other. when the secondary side iron core 22a and the primary side iron core 22b adhere tightly to each other, an effective magnetic coupling is obtained. Accordingly, a conventional electric contact made unnecessary, therefore, a danger of an electric shock is eliminated, a contact failure is improved, and safery and reliability are raised. Also, the quantity of light of a light source can be adjusted by adjusting a distance of the primary and the secondary transformer parts.