A thermal processing unit of the present invention includes: a holder that holds a plurality of substrates; a reaction container into which the holder is conveyed; a process-gas supplying mechanism that supplies a process gas into the reaction container; and a heating mechanism that heats the reaction container to conduct a film-forming process to the substrates when the process gas is supplied. Flow-rate-parameter table-data associating number-data of the substrates to be processed by one batch-process with target-data of flow-rate parameter of the process gas is stored in a flow-rate-parameter table-data storing part. A controlling unit obtains target-data of flow-rate parameter of the process gas, depending on an actual number of the substrates to be processed by one batch-process, based on the flow-rate-parameter table-data stored in the flow-rate-parameter table-data storing part, and controls the process-gas supplying mechanism according to the obtained target-data. The target-data of flow-rate parameter are determined in such a manner that a speed of the film-forming process is uniform among a plurality of batch-processes in which the numbers of substrates to be processed are different from each other.