Angles of inclination of the left and right end edges of recording paper as a recording medium are detected. In the case where it is determined an image having a size extended from an image recording region of the recording paper is recordable over the image recording region or even in the case where it is determined that the image represented by the image data is not recordable over the image recording region of the recording paper, when an input operation is performed indicating the user's intention to continue recording, an image data conversion process is performed for converting a color of a portion of the image data, which is not to be recorded in the image recording region of the recording paper, into a color of which ink is not to be ejected. Thereby, ink is ejected only to the image recording region of the recording paper.