A sheet conveying device comprising: a corrector configured to correct a position of a sheet; and at least three detectors (35, 36, 37) disposed in a sheet conveyance direction, each of the at least three detectors (35, 36, 37) being configured to detect a lateral end of the sheet according to a length of the sheet to be conveyed in the sheet conveyance direction, the corrector being configured to correct the position of the sheet based on detection results of the at least three detectors (35, 36, 37) wherein the at least three detectors (35, 36, 37) include: an upstream detector disposed upstream from the corrector in the sheet conveyance direction; a first downstream detector disposed downstream from the corrector in the sheet conveyance direction; and a second downstream detector disposed downstream from the corrector and the first downstream detector in the sheet conveyance direction, characterized in that: when it is determined that the sheet to be conveyed is relatively long in the sheet conveyance direction, the upstream detector and the second downstream detector are configured to detect the sheet and the corrector is configured to correct the position of the sheet based on detection results of the upstream detector and the second downstream detector, and when it is determined that the sheet to be conveyed is relatively short in the sheet conveyance direction, the first downstream detector and the second downstream detector are configured to detect the sheet and the corrector is configured to correct the position of the sheet based on detection results of the first downstream detector and the second downstream detector. a corrector configured to correct a position of a sheet; and at least three detectors (35, 36, 37) disposed in a sheet conveyance direction, each of the at least three detectors (35, 36, 37) being configured to detect a lateral end of the sheet according to a length of the sheet to be conveyed in the sheet conveyance direction, the corrector being configured to correct the position of the sheet based on detection results of the at least three detectors (35, 36, 37) wherein the at least three detectors (35, 36, 37) include: an upstream detector disposed upstream from the corrector in the sheet conveyance direction; a first downstream detector disposed downstream from the corrector in the sheet conveyance direction; and a second downstream detector disposed downstream from the corrector and the first downstream detector in the sheet conveyance direction, an upstream detector disposed upstream from the corrector in the sheet conveyance direction; a first downstream detector disposed downstream from the corrector in the sheet conveyance direction; and a second downstream detector disposed downstream from the corrector and the first downstream detector in the sheet conveyance direction, characterized in that: when it is determined that the sheet to be conveyed is relatively long in the sheet conveyance direction, the upstream detector and the second downstream detector are configured to detect the sheet and the corrector is configured to correct the position of the sheet based on detection results of the upstream detector and the second downstream detector, and when it is determined that the sheet to be conveyed is relatively short in the sheet conveyance direction, the first downstream detector and the second downstream detector are configured to detect the sheet and the corrector is configured to correct the position of the sheet based on detection results of the first downstream detector and the second downstream detector. when it is determined that the sheet to be conveyed is relatively long in the sheet conveyance direction, the upstream detector and the second downstream detector are configured to detect the sheet and the corrector is configured to correct the position of the sheet based on detection results of the upstream detector and the second downstream detector, and when it is determined that the sheet to be conveyed is relatively short in the sheet conveyance direction, the first downstream detector and the second downstream detector are configured to detect the sheet and the corrector is configured to correct the position of the sheet based on detection results of the first downstream detector and the second downstream detector.