The relay conveyance device includes a relay conveyance path, a plurality of conveyance members, at least one detection member and a control device. The control device executes a correction processing such that, in a state where a first sheet and a second sheet positioned at the upstream side from the first sheet are conveyed along the relay conveyance path, a sheet interval from a detection end of the first sheet by the detection member to a detection start of the second sheet by the detection member is compared with a predetermined target value, when the sheet interval is smaller than the target value, the conveyance speed of the conveyance member is decreased so as to widen the sheet interval, and when the sheet interval is larger than the target value, the conveyance speed of the conveyance member is increased so as to shorten the sheet interval.