An embodiment powder-surface treatment apparatus includes a housing defining an internal space, a main chamber installed in the internal space and defining an accommodation space in which a surface treatment process is performable using ALD, an injection unit provided on a first end portion of the main chamber, a plurality of sub-chambers arranged in a stack on top of each other in a multi-step configuration along the accommodation space in the main chamber in a state where an internal space in each of the plurality of sub-chambers is filled with a powder, a discharging unit provided on a second end portion of the main chamber, a loading apparatus configured to load a new sub-chamber into the accommodation space in the main chamber, and an unloading apparatus configured to unload and discharge at least one of the plurality of sub-chambers from the accommodation space to the outside.