The present invention absorbs displacements of a reserve tank, thereby dispersing a load caused by vibrations of a vehicle. A bracket (40) is provided with front and rear fastening points P1, P2 wherea reserve tank (30) is fixed, in the top-to-bottom direction using bolt members (4), to front and rear attachment arms (35), (36) which protrude in a lateral direction of the vehicle from positions located apart from each other across a cap opening part (23) in the front-rear direction of the vehicle. In a state where the reserve tank (30) is fixed to the vehicle body (11), the cap opening part (23) is positioned between the respective fastening points P1, P2.