To easily absorb an engine roll vibration and the displacement of an exhaust pipe system, and to secure the engine output performance sufficiently, in the connection part of an exhaust pipe divided the inside into plural exhaust routes, by partition plates.

At the connecting part structure of a dual exhaust pipes to connect rotatable two exhaust pipes 1a and 3 each other which are divided into plural exhaust routes 12 and 13 by partitioning the inside of a pipe by partion plates 11 and 31, exhaust gas drift part 11a and 11b to drift the exhaust gas flow in the left side and the right side by making the partition plate as the center are provided, and noninterference parts 33 (32) both sides are not superposed in the pipe axial direction are formed between the partition plate end part 11 at the exhaust upstream side, the exhaust drift parts 11a and 11b, and the partition plate end part 31 of the exhaust downstream side exhaust pipe 3 opposing to the upstream side partition plate end. The exhaust drift is made to flow from the noninference parts 33 (32) by the exhaust drift part, the leakage of an exhaust pulsation is reduced as low as possible, and the partition plates are made never contacted each other by the existence of the noninterference parts.