A motorcycle has an engine mounting structure in which a rear wheel supporting swing arm is vertically swung together with a rear wheel, and in which both sides in the vehicle body width direction of a vehicle body side bracket provided in a vehicle body frame are clamped between a left-right pair of engine-side brackets provided on an engine and the engine is mounted to the vehicle body side bracket through elastic members. The vehicle body frame includes a left-right pair of auxiliary brackets disposed on both sides of the vehicle body side bracket, with an interval therebetween. The left and right engine-side brackets are clamped by the auxiliary brackets. An engine supporting bolt is made to penetrate through the vehicle body side bracket, the left and right engine-side brackets and the left and right auxiliary brackets, whereby the brackets are connected to each other.