To output shared data to which data change made by another user is reflected.

Each of a plurality of PCs comprises: a data specification unit which specifies output target data from among shared data stored in a file server; and an output instruction transmission unit which transmits an output instruction to the file server. The file server comprises: an access determination unit which determines whether the output target data is being accessed (S53) in response to reception of the output instruction (S51); an output control unit which reads output target data (S55), and outputs the output target data according to output conditions (S56 to S61); and an output inhibition unit which inhibits the output target data from being read until the access determination unit determines that the output target data is not being accessed (NO at S53) when the access determination unit has determined that the target output data is being accessed (NO at S55).