PURPOSE: A sloshing reduction device is provided to prevent damage to a cargo space by suppressing sloshing regardless of the amount of liquid gas stored in a cargo space. CONSTITUTION: A sloshing reduction device comprises a pillar(110) and a surface flow reducing unit(130). The pillar is installed vertically in the cargo space of a membrane type liquefied gas carrier. The surface flow reducing unit is installed to slide along the longitudinal direction of the pillar and has lower specific gravity than the specific gravity of liquid gas. The surface flow reducing unit comprises hubs and a plurality of blades. The hub is installed in the pillar to be slidable. The blade is installed in the hub in the radial direction.
