A network scanning method and device are provided that allow an image scanning device to scan documents and transmit the scan data to a server. The image scanning device checks a connection between the image scanning device and a server, generates scan data by scanning documents, stores the generated scan data in a storage unit if a connection error exists between the image scanning device and the server, and checks whether the connection error between the image scanning device and the server is corrected. The image scanning device transmits the scan data stored in the storage unit to the server when the connection error has been corrected. Transmission of scan data is delayed until the connection error to the server is corrected, thereby reducing inconvenience in having to reset network settings after waiting until the connection error to the server has been corrected.