To provide a power plant which is capable of reducing power passing through a distributing and combining device, thereby making it possible to attain reduction of the size and manufacturing costs of the power plant and enhance driving efficiency of the same. The power plant 1 for driving driven parts DW and DW includes a prime mover 3, a first distributing and combining device 20 having first, second and third elements 21, 24 and 22, a second distributing and combining device 30 having fourth, fifth and sixth elements 31, 34 and 32, and speed-changing devices 40, 50, 2, 61 and 62 which are connected to the third and sixth elements 22 and 32 and are capable of changing the relationship between the rotational speed of the third element and that of the sixth element 32. The second and fourth elements 24 and 31 are mechanically connected to an output shaft 3a of the prime mover 3, and the first and fifth elements 21 and 34 are mechanically connected to the driven parts DW and DW.