The present invention provides a reinforcing structure of a suspension arm, in which high rigidity capable of withstanding any input from a road surface or the like can be given to the suspension arm.In a vehicle suspension including a plurality of suspension arms, one ends of which being connected to a vehicle body of a vehicle and the other ends of which being connected to a knuckle (19), a control arm (51) includes a main body (57) and a pair of attachment portions (59) provided at both ends of the main body (57). Each of the pair of attachment portions (59) is provided with a substantially cylindrical through-hole (61) for connection to the vehicle body or the knuckle (19). At least one of the pair of attachment portions (59) is provided with an annular reinforcing member (63) for reinforcing around the through-hole (61).