This sheet multifeed determination device is capable of accurately detecting a sheet multifeed state, and the sheet multifeed determination device includes: a separating member side sheet speed detecting part which detects a transport speed of a sheet surface on the separating member side of a sheet transported to a nip unit of a paper feed roll and a separating member pressure-contacting mutually; a multifeed sheet detecting part which detects presence of plural sheets in the course of being transported through the nip unit; and a multifeed state determination part which determines not to be in a multifeed state of sheets when the sheet speed detected by the separating member side sheet speed detecting part is V2.ltoreq.0 and determines to be in the multifeed state of sheets in the case of V2>0 in a condition where the multifeed sheet detecting part detects multifed sheets.