A sheet conveyer, including a first roller to rotate to convey a sheet in a conveying direction; a separator arranged to be opposed to the first roller and configured to nip the sheet and to separate the sheet from other sheets; a multiple sheet sensor arranged in a downstream position with respect to the first roller and configured to sense presence of multiple sheets, the multiple sheet sensor including an emitter and a receiver; and a second roller arranged in a downstream position with respect to the multiple sheet sensor and configured to convey the separated sheet, is provided. A component being at least one of the emitter and the receiver is arranged in an outer side position with respect to the separator, and at least a part of the component is arranged in an inner side position with respect to the second roller.