PROBLEM TO BE SOLVED: To sufficiently ensure a support strength to a magnetic circuit unit after improving vibration characteristics in an electrically driven exciter.SOLUTION: As a suspension 50 supporting a magnetic circuit unit to a coil support member 40 so as to be displaced vertically, three flexible arms 54 extending in the same circumferential direction are provided. Thus, vibration characteristics are improved while sufficiently ensuring a length of the flexible arms 54. Thereafter, arm insert grooves 40g having a vertical width approximately equal to that of the flexible arms 54 are formed at three positions in the circumferential direction in the coil support member 40. Each of the flexible arms 54 is then inserted into the arm insert grooves 40g while turning its distal end 54a in the same circumferential direction, and a barb 54a1 is engaged to an engaging part 40f1, thereby preventing the flexible arm 54 from being dropped. Thus, the magnetic circuit unit is supported for an extended length in the circumferential direction in the distal ends 54a of the flexible arms 54, and the support strength is improved.