PURPOSE: To make work instruction and control suitable by correcting either a load degree or load contents corresponding to difference between real working time and standard working time each time a worker performs line laying work and using the result for calculating electric wire load next time to grasp the progress conditions of work.

CONSTITUTION: A work data preparing means 13 sets the standard working time based on design data and electric wire load data corresponding to the existence of respective electric wires, prepares work instruction data and stores them in a storage means 11. Then, a work instruction preparing means 14 prepares a worker instruction list 15 for the worker while using staff data and work instruction data stored in the storage means 11. From the contents of that worker instruction list 15, the real working time is compared with the instructed time and a corrected value arithmetic means 18 operates the corrected values of one or plural pieces of data among load degree data, load content data and staff data. Corresponding to this result, the contents of the storage means 11 are updated by a data updating means 19 and the next work data or the like are prepared.