To provide a power transmission device for hybrid vehicles which can cope with torque cutoff on gear change and run efficiently in running based on a power generator alone and is still.

A power transmission device for hybrid vehicles has an internal engine 11 and a power generator 2 as power sources and comprises a power generator axis 22 having a power generator gear 221 rotating synchronously with the power generator 2, an input axis 3, a first output axis 4 and a second output axis 5 arranged in parallel with the input axis 3, a shift stage gear shift mechanism 8 capable of gear-changing an output inputted into the input axis 3 by one or more shift stage gear-changing gear pairs arranged between the input axis 3 and the first output axis 4, an input axis selection gear 36 always engaged directly or indirectly in the power generator gear 221, a first output axis selection gear 46 and a second output axis selection gear 52 and connection means of connecting selected gears rotating relatively with arranged individual axes to the individual axes in such a way as to be synchronously rotatable.