A scheduler generates not only normal substrate transferring schedules for substrates newly supplied to a substrate processing apparatus, but also substrate transferring schedules for keeping a high production quantity in the event of a failure. The scheduler is used in a substrate processing apparatus including a plurality of substrate processing sections for processing substrates, a transfer device for transferring the substrates, and a controller for controlling the substrate processing units to process the substrates and controlling the transfer device to transfer the substrates. The scheduler is incorporated in the controller for calculating a substrate transferring schedule and has a function to successively calculate substrate transferring schedules for substrates which are newly supplied to the substrate processing apparatus, and, in the event of a fault occurring in the substrate processing apparatus, to recalculate the substrate transferring schedules with an initial state represented by a state including the fault.