A driving force transmission device for hybrid vehicle which comprises: an engine; a rotation shaft for transmitting a rotational driving force to driving wheels; a motor for driving the rotation shaft; and a connection/disconnection switching device for switching between connection and disconnection of the driving force from the engine to the driving wheels; further comprising an auxiliary device driving mechanism at least comprising: a first auxiliary device driving shaft and a second auxiliary device driving shaft for transmitting the driving force to an in-vehicle auxiliary device; a first rotation transmission section for transmitting at least either one of the driving force of the engine and the driving force of the motor to the first auxiliary device driving shaft and the second auxiliary device driving shaft via the rotation shaft; the driving force transmission device being characterized by further comprising: a first one-way clutch mounted on the first auxiliary device driving shaft and transmitting only either one of the normal rotation and the reverse rotation of the rotation shaft from the first rotation transmission section to the first auxiliary device driving shaft; a second one-way clutch mounted on the second auxiliary device driving shaft and transmitting only either one of the normal rotation and the reverse rotation of the rotation shaft from the first rotation transmission section to the second auxiliary device driving shaft; a power transmission element for power transmission between the first auxiliary device driving shaft and the second auxiliary device driving shaft, wherein the auxiliary device driving mechanism is configured to rotate the first and second auxiliary device driving shafts (11, 12) unidirectionally in both cases where the rotation shaft is rotated in the normal direction by the rotation of the engine or the normal rotation of the motor and where the rotation shaft is rotated in the reverse direction by the reverse rotation of the motor. an engine; a rotation shaft for transmitting a rotational driving force to driving wheels; a motor for driving the rotation shaft; and a connection/disconnection switching device for switching between connection and disconnection of the driving force from the engine to the driving wheels; further comprising an auxiliary device driving mechanism at least comprising: a first auxiliary device driving shaft and a second auxiliary device driving shaft for transmitting the driving force to an in-vehicle auxiliary device; a first rotation transmission section for transmitting at least either one of the driving force of the engine and the driving force of the motor to the first auxiliary device driving shaft and the second auxiliary device driving shaft via the rotation shaft; the driving force transmission device being characterized by further comprising: a first one-way clutch mounted on the first auxiliary device driving shaft and transmitting only either one of the normal rotation and the reverse rotation of the rotation shaft from the first rotation transmission section to the first auxiliary device driving shaft; a second one-way clutch mounted on the second auxiliary device driving shaft and transmitting only either one of the normal rotation and the reverse rotation of the rotation shaft from the first rotation transmission section to the second auxiliary device driving shaft; a power transmission element for power transmission between the first auxiliary device driving shaft and the second auxiliary device driving shaft, wherein the auxiliary device driving mechanism is configured to rotate the first and second auxiliary device driving shafts (11, 12) unidirectionally in both cases where the rotation shaft is rotated in the normal direction by the rotation of the engine or the normal rotation of the motor and where the rotation shaft is rotated in the reverse direction by the reverse rotation of the motor. a first auxiliary device driving shaft and a second auxiliary device driving shaft for transmitting the driving force to an in-vehicle auxiliary device; a first rotation transmission section for transmitting at least either one of the driving force of the engine and the driving force of the motor to the first auxiliary device driving shaft and the second auxiliary device driving shaft via the rotation shaft; the driving force transmission device being characterized by further comprising: a first one-way clutch mounted on the first auxiliary device driving shaft and transmitting only either one of the normal rotation and the reverse rotation of the rotation shaft from the first rotation transmission section to the first auxiliary device driving shaft; a second one-way clutch mounted on the second auxiliary device driving shaft and transmitting only either one of the normal rotation and the reverse rotation of the rotation shaft from the first rotation transmission section to the second auxiliary device driving shaft; a power transmission element for power transmission between the first auxiliary device driving shaft and the second auxiliary device driving shaft, wherein the auxiliary device driving mechanism is configured to rotate the first and second auxiliary device driving shafts (11, 12) unidirectionally in both cases where the rotation shaft is rotated in the normal direction by the rotation of the engine or the normal rotation of the motor and where the rotation shaft is rotated in the reverse direction by the reverse rotation of the motor.