To provide a boring device and a boring method for boring holes respectively formed on opposite sides of a transaxle case 100 on the same axis by a simple structure.

In the boring device 10, a secondary sheave bearing hole 103 is bored by a boring tool 20 from the side on which the secondary sheave bearing hole 103 is formed, a through-hole 106 is bored on the same axis as the secondary sheave bearing hole 103, a hole measuring probe 30 is brought into contact with two or more positions of an inner wall of the bored through-hole 106 from the side on which a reduction drive bearing hole 104 is formed to calculate the center of the through-hole 106, and the reduction drive bearing hole 104 is bored by the boring tool 20 on the same axis as the calculated center of the through-hole 106.