A rear vehicle body structure including: a cross member which is connected between right and left rear frames extending in the front-rear direction of a vehicle body, the cross member being provided with suspension mounting parts for supporting suspensions of right and left rear wheels; spare pan frames for supporting a spare pan, the spare pan frames being connected to the cross member and extend rearward of the vehicle body from the cross member; and a pair of right and left tank frames which is connected in the vicinity of a center portion of the cross member in the right and left direction of the vehicle body, each of the pair of right and left tank frames extending in the vehicle front-right direction or the vehicle front-left direction from the cross member and being connected to a right or left floor frame or a right or left side sill.