A driving force transmitting device having a direction changing gear mechanism which transmits a rotation torque from a drive shaft to a driven shaft having an axis extending in a direction different from a direction of an axis of the drive shaft. The direction changing gear mechanism includes an output, an input gear attached to the drive shaft for restricting a relative rotation and engaged with the output gear, a gear housing rotatably supporting the output gear and the input gear under engagement condition, wherein one of the output gear and the input gear is provided with a rotation phase adjusting portion exposed outside for adjusting a rotation phase of the output gear relative to a rotation phase of the second engagement portion of the driven shaft upon the output gear being assembled to the driven shaft.