A powder supplying device for a powder coating installation with at least one closable powder container, which has a substantially cuboidal powder chamber for coating powder and a fluidizing device for introducing fluidizing compressed air into the powder chamber. At least one inlet opening is provided in a side wall of the powder container for feeding coating powder during a powder coating operation of the powder coating installation or for introducing cleaning compressed air during a cleaning operation of the coating installation. At least one outlet is provided for discharging fluidizing compressed air introduced into the powder chamber or for discharging cleaning air introduced into the powder chamber during the cleaning operation together with residual powder transported along with the cleaning compressed air. At least one powder feed line and at least one cleaning compressed-air feed line are connected via a diverter to the at least one inlet opening.