A generating apparatus includes an AC generator (11) having a stator (38) arranged around a rotary shaft (32) and a rotor (35) secured to the rotary shaft (32) and provided with an annular portion surrounding the outer peripheral portion of the stator (38) and a manual rotary driver mechanism including an accelerator (13) and engaging with a gear (33) mounted on the rotary shaft (32) and a rotary driver (12) engaging with the accelerator (13) and operative to drive the rotor (35) of the AC generator (11) to rotate through the accelerator (13) and the gear (33) so as to cause the AC generator (11) to generate electric power when the rotary driver (12) is rotated, wherein the diameter of the gear (33) mounted on the rotary shaft (32) of the AC generator (11) is set to be larger than the diameter of the rotary shaft (32) and smaller than the diameter of the annular portion of the rotor (35).