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≦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.