Abstract: An object of the present invention is to provide a reserve tank mounting structure capable of absorbing displacement of a reserve tank to disperse a load caused by vibration of a vehicle. A bracket includes front and rear fastening points for fixing a reserve tank by bolt members from a vertical direction, corresponding to front and rear mounting arms projecting in a vehicle width direction from positions spaced apart from each other in a vehicle longitudinal direction with a cap opening therebetween. In a state where the reserve tank is fixed to a vehicle body, the cap opening is disposed between the fastening points.