A data management system including a plurality of servers each having a processor, a memory, and a storage device, the system receiving and storing data using the plurality of servers and multiplexing the data, wherein the servers are provided with: a first determination unit that determines the consistency of the multiplexed data; a second determination unit that has a greater number of allowable server failures than the first determination unit for determining the consistency of the multiplexed data but a greater minimum number of times of server-to-sever communications for determining the consistency of the data; a combination unit that receives a data consistency determination result from the first determination unit or the second determination unit, and that, if the determination result includes consistency guaranteeing data, outputs the consistency guaranteed data; and a data storage unit that stores the data output by the combination unit.