An information processing apparatus for being one of a plurality of information processing apparatuses included in a parallel computer system, the information processing apparatus comprising: a main storage device configured to hold data; an arithmetic processing device including: a cache memory unit configured to hold a part of the data held in the main storage device; and an arithmetic processing unit configured to perform an arithmetic operation by using the data held in the main storage device or the cache memory unit, wherein: the arithmetic unit further includes a determination unit configured to determine whether data received from another information processing apparatus is data waited by the arithmetic processing device; the information processing apparatus further comprises: a data generation unit configured to generate padding-added data by adding padding to the data, based on adjustment information included in the received data; and a storage processing unit configured to store the padding-added data generated by the data generation unit in the main storage device or the cache memory unit; the adjustment information has adjustment size information, and the data generation unit is configured to generate the padding-added data by adding padding matched with the adjustment size information to the data; and when the determination unit determines that the received data is the data waited by the arithmetic processing device, the data generation unit is configured to generate the padding-added data and the storage processing unit is configured to store the padding-added data in the cache memory unit. a main storage device configured to hold data; an arithmetic processing device including: a cache memory unit configured to hold a part of the data held in the main storage device; and an arithmetic processing unit configured to perform an arithmetic operation by using the data held in the main storage device or the cache memory unit, wherein: a cache memory unit configured to hold a part of the data held in the main storage device; and an arithmetic processing unit configured to perform an arithmetic operation by using the data held in the main storage device or the cache memory unit, wherein: the arithmetic unit further includes a determination unit configured to determine whether data received from another information processing apparatus is data waited by the arithmetic processing device; the information processing apparatus further comprises: a data generation unit configured to generate padding-added data by adding padding to the data, based on adjustment information included in the received data; and a storage processing unit configured to store the padding-added data generated by the data generation unit in the main storage device or the cache memory unit; a data generation unit configured to generate padding-added data by adding padding to the data, based on adjustment information included in the received data; and a storage processing unit configured to store the padding-added data generated by the data generation unit in the main storage device or the cache memory unit; the adjustment information has adjustment size information, and the data generation unit is configured to generate the padding-added data by adding padding matched with the adjustment size information to the data; and when the determination unit determines that the received data is the data waited by the arithmetic processing device, the data generation unit is configured to generate the padding-added data and the storage processing unit is configured to store the padding-added data in the cache memory unit.