A sheet conveying device includes a sheet stacker, a width-direction conveyor, and circuitry. The sheet stacker stacks multiple sheets including a sheet to form a sheet bundle on the sheet stacker. The width-direction conveyor conveys the sheet bundle on the sheet stacker in a width direction of the sheet. The circuitry is to control the width-direction conveyor to convey the sheet bundle on the sheet stacker to a given position in the width direction at a first speed or a second speed slower than the first speed, based on sheet information including a length of the sheet and a processing condition related to forming the sheet bundle.