A drive transmitting extension structure and a chain saw having the drive transmitting extension structure. The chain saw also has a drive motor and a cutting head, both engaged to the drive transmitting extension structure. The drive transmitting extension structure has a first receiver member for being removably connected to the drive motor; a second receiver member for being removably secured to the cutting head; and an upper tube and a lower tube which are connected to the first and second receiver member. A drive chain is engaged to the drive motor and to the cutting head and passes through the upper tube and the lower tube. A first and second spacer member are connected to the upper and lower tubes. A first and second bolt engages adjustably the first and second spacer members respectively for holding the upper and lower tubes in the first and second receiver members.