An engine-supporting structure for a motorcycle, in which a collar can be removed to perform engine maintenance, and can be suitably re-mounted after the completion of maintenance. The engine-supporting structure supports a rear upper mounting portion of an engine, on left and right pivot plates, by providing left and right upper engine-supporting frame portions at central areas of the respective pivot plates. interposing a left upper collar between a left upper engine-supporting frame portion and a rear upper mounting portion formed on an engine, interposing a right upper collar between the right upper engine-supporting frame portion and the rear upper mounting portion formed on the engine, and coupling the left and right upper engine-supporting frame portions, the left and right upper collars, and the rear upper mounting portion by a rod-shaped member.