Vehicular power transmission device

A vehicular power transmission device comprising:

• a driving force source;
• a tapered roller bearing;
• a case member including an end surface, the end surface including a convex streak provided with a first assembled surface, a part of the convex streak provided on the end surface such that the part of the convex streak passes through a region corresponding to an outer race of the tapered roller bearing;
• a rotary shaft that transmits a driving force from the driving force source, the rotary shaft being supported in a rotating manner in a circumferential direction of the rotary shaft via the tapered roller bearing while being pressurized in a direction of a rotational centerline of the rotary shaft, in the case member, and one end of the rotary shaft being supported in a rotating manner by the end surface of the case member via the tapered roller bearing;
• a fastened state where the driving force source is fastened to the first assembled surface being one of a state where the driving force source is fastened to the first assembled surface via a fixed component, and a state of where the driving force source is directly fastened to the first assembled surface;
• and
• a concave portion provided in at least one of the first assembled surface, and other assembled surfaces for fastening the driving force source, in the region corresponding to the outer race of the tapered roller bearing, the other assembled surfaces provided to one of the fixed component and the driving force source.