A sheet delivery mechanism includes a pair of delivery rollers which deliver a sheet along a sheet delivery passage of a sheet treatment apparatus for predeterminately treating the sheet, a sheet halting member for halting the sheet, and a pinching force adjusting member. The pinching force adjusting member adjusts the delivery rollers to place them into a first state where the sheet pinching force of the delivery rollers is relatively small so that the delivery rollers can slip on the halted sheet and into a second state where the sheet pinching force is relatively great so that the sheet can be delivered in the case where a sheet halt is released for delivery.
