An electric power generating apparatus for use in an aircraft, the electric power generating apparatus comprising: a manual transmission configured to change speed of rotational power of an aircraft engine and including a plurality of gear stages; and an electric power generator to which the rotational power which has been changed in speed by the manual transmission is transmitted, wherein the manual transmission includes a planetary gear mechanism, an input shaft connected to a carrier holding a planetary gear of the planetary gear mechanism, an output shaft connected to a sun gear of the planetary gear mechanism, and a brake connected to a ring gear of the planetary gear mechanism, characterized in that: the electric power generating apparatus further comprises a continuously variable transmission to which the rotational power from the output shaft of the manual transmission is input and which outputs the rotational power to the electric power generator, the manual transmission further includes a one-way clutch which is sandwiched between the input shaft and the output shaft and by which the rotational power of the input shaft is transmitted to the output shaft, the continuously variable transmission and the electric power generator are arranged such that an axis of the continuously variable transmission and an axis of the electric power generator are parallel to each other when viewed from at least one direction; and when viewed from a direction along the axes (X2, X3), the manual transmission is arranged so as to overlap the continuously variable transmission and the electric power generator. a manual transmission configured to change speed of rotational power of an aircraft engine and including a plurality of gear stages; and an electric power generator to which the rotational power which has been changed in speed by the manual transmission is transmitted, wherein the manual transmission includes a planetary gear mechanism, an input shaft connected to a carrier holding a planetary gear of the planetary gear mechanism, an output shaft connected to a sun gear of the planetary gear mechanism, and a brake connected to a ring gear of the planetary gear mechanism, a planetary gear mechanism, an input shaft connected to a carrier holding a planetary gear of the planetary gear mechanism, an output shaft connected to a sun gear of the planetary gear mechanism, and a brake connected to a ring gear of the planetary gear mechanism, characterized in that: the electric power generating apparatus further comprises a continuously variable transmission to which the rotational power from the output shaft of the manual transmission is input and which outputs the rotational power to the electric power generator, the manual transmission further includes a one-way clutch which is sandwiched between the input shaft and the output shaft and by which the rotational power of the input shaft is transmitted to the output shaft, the continuously variable transmission and the electric power generator are arranged such that an axis of the continuously variable transmission and an axis of the electric power generator are parallel to each other when viewed from at least one direction; and when viewed from a direction along the axes (X2, X3), the manual transmission is arranged so as to overlap the continuously variable transmission and the electric power generator. the electric power generating apparatus further comprises a continuously variable transmission to which the rotational power from the output shaft of the manual transmission is input and which outputs the rotational power to the electric power generator, the manual transmission further includes a one-way clutch which is sandwiched between the input shaft and the output shaft and by which the rotational power of the input shaft is transmitted to the output shaft, the continuously variable transmission and the electric power generator are arranged such that an axis of the continuously variable transmission and an axis of the electric power generator are parallel to each other when viewed from at least one direction; and when viewed from a direction along the axes (X2, X3), the manual transmission is arranged so as to overlap the continuously variable transmission and the electric power generator.