A power transmitting device having a main input shaft selectively connected to an output shaft of an engine by a main clutch CM; first and second sub input shafts disposed coaxially and selectively connected to the main input shaft by clutches C1 and C2, respectively; an output shaft connected to the first and second sub input shafts via a pair of gears, respectively, and outputting motive power to driving wheels via a counter shaft; and a deceleration mechanism configured to be capable of differentially rotating a sun gear, which is connected to the main input shaft and an electric motor, a ring gear, and a carrier, which is connected to the first sub input shaft, with respect to one another and transmitting the motive power to the output shaft via the carrier. A brake B capable of locking the ring gear is connected to the ring gear.