an image forming apparatus having functions of a scanner , a printer , and a facsimile includes a rectangular recording sheet , a first sheet cassette to enclose the recording sheet in a first direction , a second sheet cassette to enclose the recording sheet in a second direction different from the first direction by 90 °, an input unit to input first and second image data in the first direction , a rotating unit to rotate the second image data from the input unit in the second direction , an image forming unit to form an image based on the first image data from the input unit or the second image data from the rotating unit onto the recording sheet fed from the first or second sheet cassette , and a feeder for feeding the recording sheet in the first sheet cassette to the image forming unit when the input unit inputs the first image data and for feeding the recording sheet in the second sheet cassette to the image forming unit when the input unit inputs the second image data .