A vehicle battery device includes: a battery cell mounting part accommodating a battery cell group constituted by a plurality of laminated battery cells and having a temperature control solution passage along a lamination direction of the battery cells; and an interface box, wherein the battery cell mounting part is connected to at least one of two side surfaces of the interface box; the interface box has, on any outer surface other than the side surface connected with the battery cell mounting part, a power interface part transmitting and receiving electricity and a temperature control solution interface part transmitting and receiving a temperature control solution; the battery cell group is electrically connected to the power interface part; and the temperature control solution passage is connected to the temperature control solution interface part so as to be capable of circulating the temperature control solution.