1. A transportation state notification method, comprising: detecting a plurality of types of events relating to lot transportation in a plurality of temporary storage devices which are provided at different locations, to which lots are transported, and in which the lots are stored; updating lot state data including data indicating an event transition of each of the lots based on the detected events; and determining whether the lots are in a state of “under transportation” or “awaiting transportation” based on the data indicating the event transition, and displaying an image showing a state of a target lot at a predetermined time as an image showing a transportation load state.