Device at cool cargo spaces (1), for securing the cargo sideways, and comprising at least one inflatable body (6) provided between the side wall of the hold (2) and the cargo space (1), whereby said at least one body (6) is arranged in inflated state to fill out essentially all space (3) between the side wall (2) and the cargo, not used for cargo, and thereby at the same time to reduce the volume of cooling air required for cooling the cargo space.