Abstract: A robot body (21) is carried into the water chamber (2A) of a condenser (1) and disposed on a tube sheet (4) through which a number of narrow tubes (3) open. Inner nozzles (23) are inserted into narrow tubes (3) from working devices (24) installed on the front ends of four combined-use arms (22A through 22D) to position and fix the robot body (21). And the arm turning motors (25) and arm extending and contracting cylinder devices (26) of the combined-use arms (22A through 22D) are driven to move the robot body (21). Further, a cleaning brush (12) and a flaw detection probe (13) are inserted into a narrow tube (3) from each working device (24) and moved along the narrow tube (3) by cleaning water, whereby cleaning and inspection are performed. With three of the combined-use arms (22A through 22D) fixed to the narrow tubes (3), the inner nozzle (23) is extracted from the narrow tube (3) and the working device is moved to the next narrow tube (3).