A sheet transporting device including: a sheet feeding section that feeds plural sheets to a transporting path; three or more roller pairs that are arranged along the transporting path; a double feed detecting section that detects a length of a double feed portion when sheets are fed in an overlapped manner; a selecting section that selects two of the three or more roller pairs based on the length of the double feed portion; and a transport control section that can change a transporting speed of at least one of the selected roller pairs, wherein the selecting section selects two roller pairs that have a space between which the double feed portion can be positioned, and the transport control section controls the transporting speeds of the selected roller pairs such that the speeds differ from each other to separate the delaying sheet from the preceding sheet.