A communication apparatus can transmit image data stored in a memory in a manner capable of reducing the running cost. The number of input lines for each page is recognized for image data of a plurality of pages input and stored in the memory. When transmitting the stored image data of the plurality of pages, the number of recordable lines per page of a recording sheet used in a communication partner's terminal is recognized, and image data for one page obtained by combining image data of a plurality of consecutive pages is transmitted. The reception side combines a maximum number of image data for a plurality of pages recordable on a single recording sheet, and transmits the obtained image data as image data for one page. Image data of different files for the same communication partner are also combined in the above-described manner.