Provided is a method of managing inventory, the method including receiving location information indicating at least one space location among a plurality of space units and space information corresponding to the location information, calculating a state change amount related to the at least one space location based on at least one of the location information, the space information, and information on a previous space state for each of the plurality of space units, or updating the information on the previous space state for each of the plurality of space units with information on a current space state based on the state change amount. An inventory management apparatus performing the method is provided. A non-transitory computer readable recording medium for performing the method is provided.