A method of preparing a schedule for a substrate processing apparatus. A plurality of lots are processed by the substrate processing apparatus including a plurality of processing sections for processing substrates. An order of processing the lots is determined based on a recipe including a plurality of processing steps for successively processing the lots in the processing sections. The method includes, in determining the processing order, a step of allocating a first processing step for one of the lots, and thereafter allocating, as a next processing step, one of next processing steps for the lots preceded by a processing step having the earliest