To improve installing performance by easily fastening retainer installing bolts by arranging bracket installing bosses in the vicinity of the axis of a transfer pinion shaft without overlapping with the retainer installing bolts so that the retainer installing bolts do not interfere with the bracket installing bosses.

In a transfer of a 4WD vehicle using an FF vehicle as a base, a retainer 26 is installed in a transfer case, and a transfer pinion shaft pointing in the longitudinal direction of a vehicle is journalled to this retainer 26. When installing such a retainer 26 in the transfer case, respective retainer installing bolts 50 are thread-mounted on a case side installing boss after being inserted into respective retainer installing bolt holes 48. At this time, since bracket installing bosses 56-1, 56-2 are arranged so as not to interfere with retainer installing bolts 50-1, 50-2, the retainer installing bolts 50-1, 50-2 can be easily fastened to improve the installing performance.