To maintain the latest state of data on the side of a host computer for managing various data in a data managing system composed of the said host computer and plural terminals capable of updating the data on this host computer.

This system is composed of a host computer 10 for managing various data 15 and terminals 30 for updating the data 15 through communication lines 20. In this case, update data are prepared on the side of the terminal 30 and transmitted to the host computer 10 together with the date and time of updating, and the host computer 10 manages the final updating date of the data 15 in an updating date managing table 16, compares the updating date with the final updating date of updating object data when updating the data 15 based on the update data transmitted from the terminal 30 and updates the data 15 only when the first date is later so that the data 15 can be maintained in the latest state at all the time.