A rotary electric machine system of a combined power system includes a rotary electric machine, a rotary electric machine housing in which the rotary electric machine is accommodated, and a rotation parameter detector that detects a rotation parameter of a rotating shaft constituting the rotary electric machine. The rotating shaft includes a first end part and a second end part, a first bearing is provided between the first end part and the housing, and a second bearing is provided between the second end part and the housing. The first end part includes a protruding distal end that passes through the first bearing and protrudes to an exterior of the housing. The rotation parameter detector is disposed on the protruding distal end.