PURPOSE: To obviate the need for executing the change of a program with a line equipment being stopped each time due to the conditions change of a line, by executing work with a work robot itself detecting the contents of the work onto a work object.

CONSTITUTION: The work information of a proper work object is memorized on an information memory medium 3, this information memory medium 3 is flowed to a transfer line in the set with a work object 2, and a work robot 8 detects the position of the information memory medium 3 by a sensor, then this information memory medium 3 is directly set in a data in and output part 7, and the work information is fed to the robot 8 with an information in and output part 7 reading it. According to this fed work information the work robot 8 executes work for the work object 2, after completion of the work the information in and output part 7 writes the work information in the information memory medium 3 with its renewing, after the writing the work robot 8 takes the information memory medium 3 from the information in and output part 7 returning it to the specific position of a transfer line.