PURPOSE: To on-line-process managing item processes, design assistance processes, and field photograph transmission processes, by mutually connecting together a construction managing center, construction field offices, and personal computers through a LAN.

CONSTITUTION: Respective hardware connecting together utilization relations of a host and users among a construction managing center, a plurality of construction field offices, and a plurality of construction fields are connected together through a LAN. Otherwise, personal computers are mutually connected together, and this system is provided with input/output means, data transmission means 2, 2', text data processing means 3, image data processing means 4, for constituting a network outside premises. By constituting the system in this way, the whole or a part of construction managing item processes, construction technical calculation processes, and field photograph transmission processes are held in common through an auxiliary memory means 5 for managing files, and on-line-processed.