A calculation processing apparatus, which executes network calculations by a hierarchical network configured by connecting a plurality of logical processing nodes that execute calculations for input data to generate calculation result data, calculates memory sizes of buffers required for the network calculations, based on the configuration of the network calculations, in association with a plurality of types of buffer assignment methods for assigning storage areas for intermediate buffers used to hold calculation result data in correspondence with the plurality of processing nodes which configure the network, and executes the network calculations using buffers assigned by the buffer assignment method, which is selected based on the calculated memory size, in the execution sequence according to that buffer assignment method.