PREVENTION STRUCTURE FOR WRONG INSERTION OF BATTERY

PROBLEM TO BE SOLVED: To provide a wrong insertion preventing structure of a battery-housing box, that is simple in construction and easy in assembling and has a low manufacturing cost. SOLUTION: A battery-housing portion 1 comprises the first partition plate 4, which is arranged in a position at a certain distance from a plus voltage terminal 2 and which has a notched U-shape larger than the diameter of a protrusion constituting the plus electrode of a battery and smaller than the diameter of the minus electrode, and the second partition plate 5, which is arranged in a position at a predetermined distance from the first partition plate and which has the same shape as the first partition plate. When the first battery is pushed in so that its negative electrode may come into contact with the second partition plate 5 and its plus electrode is put along the U-type groove of the first partition plate 4, a leaf spring of the plus voltage terminal 2 is pressurized downwardly by the protrusion of the plus electrode, and the battery is fixed. When the plus electrode of the second battery is inserted along the U-type groove of the second partition plate 5, and its negative electrode is intruded in contact with a negative voltage terminal 3, a leaf spring of the negative voltage terminal 3 is pressurized by the negative electrode, and the battery is fixed.