An air cavity vessel having longitudinal and transverse partitions is provided. The air cavity vessel, which injects air into the bottom thereof to form air layers in order to reduce resistance of the vessel, includes transverse partitions partitioning the bottom in a transverse direction, longitudinal partitions partitioning the bottom in a longitudinal direction, spatial areas defined in a grid pattern by the transverse partitions and the longitudinal partitions, an air supply unit installed in a forebody of the vessel and supplying compressed air into the spatial areas, and a compressor for supplying the compressed air to the air supply unit. Thereby, multiple air layers are formed on a bottom flat area on a small scale.