Shortly after the great earthquake on Sept. 1, 1923, the writer had an opportunity of visiting more than fifty factories and power plants in the devastated area in City of Tokyo and its environs. Under the items of chimney, boiler, piping, factory building etc., he gives full description of the damage of the factories and their equipments from his personal observation. He analyses the cause of the damage and points out what part is most liable to be wrecked by the earthquke. As the conclusion he suggests the means to avoid the damage or to make the loss as little as possible.