An electronic document generation system includes an image forming apparatus that generates a scanned image of an original document, and an external terminal that generates an electronic document based on image data regarding the scanned image received from the image forming apparatus. The image forming apparatus includes an auxiliary data generation unit that generates auxiliary data to be used in processing for generating the electronic document, and a communication unit that transmits the auxiliary data to the external terminal. The external terminal includes a document generation unit that uses the auxiliary data received from the image forming apparatus to generate the electronic document based on the image data regarding the scanned image in cooperation with an external cooperative device different from the external terminal. The document generation unit generates the electronic document by complementing the result of processing performed on the image data with the auxiliary data.