AUTOMATIC ORIGINAL CONVEYANCE DEVICE, ORIGINAL READER, AND IMAGE FORMATION APPARATUS

PROBLEM TO BE SOLVED: To make a size determination of many sizes, especially a small size of an original, while accurately determining whether the next original is present without increasing the number of original length sensors.SOLUTION: An automatic original conveyance device includes: a plurality of original length sensors 27, a rear end detection sensor 25, and an original set sensor 18, and determines a length of an original 1 by signals from the original length sensors 27. When the original length sensors 27 cannot detect the length of the original 1, the length of the original 1 is determined using a signal from the rear end detection sensor 25. At this time, when the original length is determined based on the fact that the rear end detection sensor 25 does not detect the original 1, the presence or absence of the next original is determined on the basis of a detection result of the original set sensor 18 after a detection signal from the original set sensor 18 becomes stable.