PURPOSE: To integrate the dates and the times among plural terminal computers by correcting the data and the time of the terminal computer which is started by the reference date and time stored in a network control computer as the start of each terminal computer.

CONSTITUTION: Plural terminal computers PC1 - PCn are connected to a network control computer 1 which controls the network communication among the computers PC1 - PCn via a communication network such as a LAN consisting of a communication cable 2 and an adaptor device 3. Then the computer 1 receives the identification names from the computers PC1 - PCn that started the network communication and refers to a fact whether the dates and the times are corrected or not by reference to a table and based on those received identification names. If not, the computer 1 returns the data on the dates and the times to instruct the computers PC1 - PCn to correct their own dates and times. Thus the dates and the times are integrated among the computers PC1 - PCn.