1. A calculation processing apparatus, which executes calculation processing based on a network composed by hierarchically connecting a plurality of processing nodes, said apparatus comprising: a processor and a memory, said processor and said memory cooperating to function as: a memory control unit configured to assign a partial area of a memory to each of the plurality of processing nodes, store a calculation result of each processing node in a storable area of the partial area assigned to that processing node, and set, as storable areas, areas that store the calculation results whose reference by all processing nodes connected to a subsequent stage of that processing node is complete; a designation unit configured to designate a processing node, which is to execute calculation processing, of the plurality of processing nodes; a determination unit configured to determine, based on storage states of calculation results in partial areas of the memory assigned to the processing node designated by said designation unit and to processing nodes connected to a previous stage of the designated processing node, whether or not to execute a calculation of the designated processing node; and an execution unit configured to, when said determination unit determines that the calculation is executed, control to execute calculation processing corresponding to the designated processing node.