PROBLEM TO BE SOLVED: To restrain deterioration of communication quality due to abrasion powder while inhibiting abrasion of a brush by lubricating oil, and reduce the maintenance work cost.SOLUTION: A brush base plate 10 is fitted to a brush mounting metal fitting 9. The brush base plate 10 is normally opposite and parallel to a slip ring 7. The brush base plate 10 is supported on the brush mounting metal fitting 9 turnably around an axis orthogonal to the advancing direction of the slip ring 7. A small-sized servo motor 17 as base plate displacing means for turning the brush base plate 10 is fitted to the brush mounting metal fitting 9. The small-sized servo motor 17 rotates the brush base plate 10 through a motor gear 18 and a mounting metal fitting gear 15 to thereby change the attitude (the inclination angle) of the brush base plate 10 to the slip ring 7.
