A power storage housing device, comprising: a first side surface having a plurality of air inlets including a first air inlet and a second air inlet for leading an outside air into inside, the second air inlet being formed at upper position on the first side surface and the first air inlet being formed at a lower position on the first side surface; a second side surface disposed to face the first side surface, having an exhaust port at an upper portion thereof; a first shelf plate provided at a position lower than the exhaust port and higher than the first and second air inlets, having an opening close to the second side surface for sending an inside air to the exhaust port; a plurality of second shelf plates having a heat transfer property, at least one second shelf plate being provided at a higher position than the first air inlet, and having an opening for sending up the inside air fed from the first air inlet; and module cases in a substantially rectangular parallelepiped shape, the module cases including side surfaces having longitudinal side portions, each module case being fixed to a respective second shelf plate in a longitudinal direction thereof directed along a flow direction of the inside air, each module case housing a battery group, the air inlets being provided at positions corresponding to the respective module cases; and highly heat conductive members each having a heat transfer surface in contact with at least one of the longitudinal side surfaces of a respective module case and fixed to diffuse a heat flow on the side surface of the module case, with a side portion of the heat transfer surface being in contact with the respective second shelf plate to enlarge a heat radiation area to the air. a first side surface having a plurality of air inlets including a first air inlet and a second air inlet for leading an outside air into inside, the second air inlet being formed at upper position on the first side surface and the first air inlet being formed at a lower position on the first side surface; a second side surface disposed to face the first side surface, having an exhaust port at an upper portion thereof; a first shelf plate provided at a position lower than the exhaust port and higher than the first and second air inlets, having an opening close to the second side surface for sending an inside air to the exhaust port; a plurality of second shelf plates having a heat transfer property, at least one second shelf plate being provided at a higher position than the first air inlet, and having an opening for sending up the inside air fed from the first air inlet; and module cases in a substantially rectangular parallelepiped shape, the module cases including side surfaces having longitudinal side portions, each module case being fixed to a respective second shelf plate in a longitudinal direction thereof directed along a flow direction of the inside air, each module case housing a battery group, the air inlets being provided at positions corresponding to the respective module cases; and highly heat conductive members each having a heat transfer surface in contact with at least one of the longitudinal side surfaces of a respective module case and fixed to diffuse a heat flow on the side surface of the module case, with a side portion of the heat transfer surface being in contact with the respective second shelf plate to enlarge a heat radiation area to the air.