A sheet transferring device includes a feeding roller configured to feed a sheet; a transferring roller configured to transfer the sheet to the feeding roller; a sheet sensor configured to detect the sheet at a sheet transferring part from the transferring roller to the feeding roller; a measuring part configured to measure an interval of a rear end of a prior sheet and a head end of a following sheet based on a sheet detection signal of the sheet sensor; and a transferring control part configured to adjust a sheet transferring speed of the transferring roller so that the interval between the prior sheet and the following sheet is adjusted to a set value as corresponding to the interval measured by the measuring unit.