A vehicle comprising a battery unit adapted to be disposed under a floor panel, the battery unit comprising: a battery case having an inlet at a front end to let in a cooling gas, first and second outlets (555, 556) at a rear end to let out the cooling gas, a front battery storage provided on a front side in a front-back direction, a rear battery storage provided on a rear side in the front-back direction, the front-back direction being oriented from the first end to the second end, and a central battery storage provided between the front battery storage and the rear battery storage; a plurality of battery modules stored and held in the battery case, at least one of the battery modules being disposed in the front battery storage, at least one of the battery modules being disposed in the rear battery storage, at least one of the battery modules being disposed in the central battery storage; and a bypass structure whereby part of the cooling gas bypasses the battery modules arranged on the side of the front end of the battery case at which the inlet is formed, the vehicle being characterized in that the bypass structure comprises: a bypass exit opening formed on the front end of a top of the battery case on an opposite side of the inlet in a width direction traversing the front-back direction; a bypass entrance opening formed in a central part of the top of the battery case in the front-back direction and in a central part along the vehicle in the width direction; a bypass duct attached on the top of the battery case to cover from the bypass exit opening to the bypass entrance opening to guide the cooling gas flowing out from the bypass exit opening to the bypass entrance opening, the bypass duct being configured to allow a part of the cooling gas bypassing the at least one of the battery modules in the front battery storage; and a flow path (533 (532a, 533c, 533d)) having a first flow path and a second flow path formed inside the battery case to guide the cooling gas downstream of the bypass entrance opening toward the rear battery storage to both sides in the width direction for cooling off the battery modules in the central battery storage. a battery case having an inlet at a front end to let in a cooling gas, first and second outlets (555, 556) at a rear end to let out the cooling gas, a front battery storage provided on a front side in a front-back direction, a rear battery storage provided on a rear side in the front-back direction, the front-back direction being oriented from the first end to the second end, and a central battery storage provided between the front battery storage and the rear battery storage; a plurality of battery modules stored and held in the battery case, at least one of the battery modules being disposed in the front battery storage, at least one of the battery modules being disposed in the rear battery storage, at least one of the battery modules being disposed in the central battery storage; and a bypass structure whereby part of the cooling gas bypasses the battery modules arranged on the side of the front end of the battery case at which the inlet is formed, the vehicle being characterized in that the bypass structure comprises: a bypass exit opening formed on the front end of a top of the battery case on an opposite side of the inlet in a width direction traversing the front-back direction; a bypass entrance opening formed in a central part of the top of the battery case in the front-back direction and in a central part along the vehicle in the width direction; a bypass duct attached on the top of the battery case to cover from the bypass exit opening to the bypass entrance opening to guide the cooling gas flowing out from the bypass exit opening to the bypass entrance opening, the bypass duct being configured to allow a part of the cooling gas bypassing the at least one of the battery modules in the front battery storage; and a flow path (533 (532a, 533c, 533d)) having a first flow path and a second flow path formed inside the battery case to guide the cooling gas downstream of the bypass entrance opening toward the rear battery storage to both sides in the width direction for cooling off the battery modules in the central battery storage. a bypass exit opening formed on the front end of a top of the battery case on an opposite side of the inlet in a width direction traversing the front-back direction; a bypass entrance opening formed in a central part of the top of the battery case in the front-back direction and in a central part along the vehicle in the width direction; a bypass duct attached on the top of the battery case to cover from the bypass exit opening to the bypass entrance opening to guide the cooling gas flowing out from the bypass exit opening to the bypass entrance opening, the bypass duct being configured to allow a part of the cooling gas bypassing the at least one of the battery modules in the front battery storage; and a flow path (533 (532a, 533c, 533d)) having a first flow path and a second flow path formed inside the battery case to guide the cooling gas downstream of the bypass entrance opening toward the rear battery storage to both sides in the width direction for cooling off the battery modules in the central battery storage.