A power unit includes a cam damper mechanism having a cam member reciprocally and unrotatably provided on one of a pair of bevel gears, and rotatably provided on an extended shaft; a lifter member slidably and unrotatably provided on the extended shaft in an axial direction; a damper spring configured such that one end portion thereof is supported on a first flange portion of the extended shaft, and the other end portion thereof biases the lifter member toward the cam member in an axial direction by abutting on the lifter member, and the biasing force is supported by the one bevel gear. The extended shaft has the one of the bevel gears and the cam damper mechanism between the first flange portion and a first bearing, and is accommodated in the bevel gear case so as to be fixed to a bevel gear holder along with the first bearing.