A battery unit holding device that holds a battery unit in place includes a fixing part, a fixed part, and a positioning part provided between the vehicle body and the battery unit for positioning the battery unit on the vehicle body. The fixed part has a support shaft extending in a first direction that corresponds to one of a longitudinal direction and a width direction of the vehicle body and supports the load acting downwardly on the battery unit. The fixing part is movable along the support shaft while holding the support shaft at a middle position thereof. When a first impact greater than a first preset force is applied to the vehicle body in the first direction, the positioning part permits the fixing part to move in the first direction along the support shaft from the middle position of the support shaft.