A first guide member includes a concave-shaped guide surface. A recording medium such as a sheet fed by register rollers takes a curved position while being fed in a sheet feeding direction such that the leading edge of the sheet slides on the guide surface. A space is defined between the sheet and the guide surface due to the stiffness of the sheet. Thus, the sheet smoothly curves. When a speed of conveying the sheet by the register rollers is faster than a speed of conveying the sheet by a conveying belt, slack in the sheet is allowed in the space defined between the sheet and the guide surface. Therefore, the sheet can be stably conveyed without applying excessive load to the sheet or a sheet conveying device.