Abstract: To adjust the posture of a sheet being conveyed, movable checker members provided adjacent to the conveyance path for the sheet are once driven in the direction of conveyance of the sheet before the members touch the sheet and are subsequently decelerated, the members being caused to abut against the front end of the sheet during the deceleration, thereby checking the sheet and thus correcting any skew thereof. Further, for positioning the sides of the sheet, the sheet is taken out of a hopper by way of a separating device and is guided and fed in such a manner that its front corner will not be caused to abut against a side registration guide, and subsequently the sheet is conveyed toward the guide by way of obliquely extending conveyer belt devices and one side of the sheet is brought into contact with the guide for positioning after a front corner of the sheet has passed at least the edge of the guide.