A sheet transport apparatus, comprising: a folding cylinder for transporting sheets one by one or as a stack of a plurality of the sheets; a first transport cylinder (13; 12) having first holding means (65a to 65f; 111a to 111d), which holds the sheet, at a plurality of locations in a circumferential direction, and being adapted to hold the sheets by all of the first holding means and transport the sheets when the sheets are trans-ported one by one, and hold the sheets by alternate ones of the first holding means and transport the sheets when the sheets are transported as the stack of the plurality of sheets; a second transport cylinder opposing the first transport cylinder, having second holding means (80a, 80b; 113a to 113d), which holds the sheet, at a plurality of locations in a circumferential direction, and being supported rotatably; a third transport cylinder opposing the first transport cylinder, having third holding means (90a, 90b; 115b, 115d), which holds the sheet, at a plurality of locations in a circumferential direction, and being supported rotatably; and switching means for switching transport paths, characterized in that the switching means for switching transport paths comprise a cam mechanism (67, 68, 69, 75, 83, 94, 96, 97; 120, 123, 125, 128, 132) and are adapted such that when the sheets are transported one by one, the sheets held by all of the first holding means (65a to 65f; 111a to 111d) are alternately transported to the second holding means (80a, 80b; 113a to 113d) and the third holding means (90a, 90b; 115b, 115d), and when the sheets are transported as a stack, the sheets held by alternately ones of the first holding means (65a to 65f; 111a to 111d) are alternately trans-ported to the second holding means (80a, 80b; 113a to 113d) and the third holding means (90a, 90b; 115b, 115d). a folding cylinder for transporting sheets one by one or as a stack of a plurality of the sheets; a first transport cylinder (13; 12) having first holding means (65a to 65f; 111a to 111d), which holds the sheet, at a plurality of locations in a circumferential direction, and being adapted to hold the sheets by all of the first holding means and transport the sheets when the sheets are trans-ported one by one, and hold the sheets by alternate ones of the first holding means and transport the sheets when the sheets are transported as the stack of the plurality of sheets; a second transport cylinder opposing the first transport cylinder, having second holding means (80a, 80b; 113a to 113d), which holds the sheet, at a plurality of locations in a circumferential direction, and being supported rotatably; a third transport cylinder opposing the first transport cylinder, having third holding means (90a, 90b; 115b, 115d), which holds the sheet, at a plurality of locations in a circumferential direction, and being supported rotatably; and switching means for switching transport paths, characterized in that the switching means for switching transport paths comprise a cam mechanism (67, 68, 69, 75, 83, 94, 96, 97; 120, 123, 125, 128, 132) and are adapted such that when the sheets are transported one by one, the sheets held by all of the first holding means (65a to 65f; 111a to 111d) are alternately transported to the second holding means (80a, 80b; 113a to 113d) and the third holding means (90a, 90b; 115b, 115d), and when the sheets are transported as a stack, the sheets held by alternately ones of the first holding means (65a to 65f; 111a to 111d) are alternately trans-ported to the second holding means (80a, 80b; 113a to 113d) and the third holding means (90a, 90b; 115b, 115d).