A hypoid reducing device that allows the coupling/connection between a hypoid gear set and a motor to be more flexible and have a wider applicability. A hypoid pinion shaft is supported by two bearings in a bearing case portion in a gear case. A hypoid pinion engages with a hypoid gear having an orthogonal axial line. The hypoid pinion shaft is provided with a base end portion that is a solid shaft portion projecting toward a motor beyond the bearing on the motor side. The motor and the bearing case portion of the hypoid gear set are coupled with a separately provided joint case, while the motor output shaft and the base end portion of the hypoid pinion shaft are coupled through coupling members in the joint case.