A reduction in network load as well as an increase in speed of response through caching and an increase in communication efficiency through buffering are both achieved. A data storage control system that temporarily stores and controls data exchanged between a user terminal 1 and an online storage device 3 includes a storage unit 24 that temporarily stores receive data read from the online storage device 3 by the user terminal 1 and transmit data to be written in the online storage device 3 by the user terminal 1, and a data transmission unit 12 and a data control unit 23 that cause new storage of the transmit data in the storage unit 24 to wait in a case where a volume of the transmit data stored in the storage unit 24 is greater than a threshold value and/or in a case where an elapsed time from a last access to the receive data that is planned to be deleted next time among the receive data stored in the storage unit 24 is shorter than a threshold value.