With regard to a group of substrates preceding a substrate of which residence time is under calculation, a time t1 and a time t2 are calculated, t1 being a time interval from a time point in which a substrate B1 under the consideration has become ready from being transferred out from a wait module to a time point in which a heating module used for the substrate B1 has been ready for processing the substrate B1, t2 being a time interface from a time on in which the substrate B1 under calculation has been transferred out from the wait module to a time point of reaching the heating module used for the substrate B1, and a waiting time t of the substrate B1 in the wait module is calculated according to t=t1-t2.