A vehicle mounting structure for a fuel cell includes a fuel cell box which accommodates a fuel cell stack inside. The fuel cell box includes a bottom frame on which the fuel cell stack is mounted, a top frame, the bottom frame and the top frame sandwiching the fuel cell stack, a side frame which forms a framework of the fuel cell box and which is connected to the bottom frame and to the top frame, a bottom holddown member which fixes a bottom portion of the fuel cell stack to the bottom frame, and a top holddown member which fixes a top portion of the fuel cell stack to the top frame. Structural members which are required to carry a fuel cell stack are reduced in weight and miniaturized in size while ensuring the desired installation rigidity when the fuel cell stack is carried.