In a vehicle battery mounting structure, each sidewall of a bracket body has a load-receiving portion extending obliquely from the vehicle vertical direction upper end of a base portion toward the vehicle vertical direction lower end of a flat wall. The load-receiving portion is located between a rear wall and an intermediate beam. Thus, when the intermediate beam is moving toward the vehicle longitudinal direction front side during a rear collision, or the like, a front wall of the intermediate beam smashes against the load-receiving portion.