Driving force transmission device

A drive force transmission device comprising:

• an input shaft to which rotational drive force from a drive source is input;
• a first joint that is linked to the input shaft;
• an output shaft to which the rotational drive force is output;
• a second joint that is linked to the output shaft;
• and an intermediate shaft connecting the first joint and the second joint, wherein
• a drive force transmission path from the input shaft to the output shaft includes a plurality of fitting portions that is provided with a spline shaft portion that has a plurality of spline teeth and a spline groove portion that has a plurality of fitting grooves that fits to the plurality of spline teeth, and
• the plurality of fitting portions includes a first fitting portion and a second fitting portion in which the plurality of spline teeth is twisted with respect to rotation axial lines, and torsional directions of the plurality of spline teeth differ between the first fitting portion and the second fitting portion.