As known from Japanese Patent Laid-open Publication JP 2008-255877 (hereafter called Patent Document 1), air-blow work machines are known. Machines of this type are used to blow fallen leaves, rubbishes, waste cans, and so on, to clean the ground. They are generally called power blowers as often called in this application as well. These power blowers have a blower tube, which is typically a plastic mold, coupled to a blower main body. In operation, a high-speed airflow is blown out from the distal end of the blower tube. A user of such a power blower may direct the distal end of the blower tube toward fallen leaves, etc. on the ground to blow and gather them with a high-speed airflow from the blower tube. While the power blower disclosed by the said Publication JP 2008-255877 is a hand-held one, also known are a backpack type power blower whose main body is carried on a user's back in operation (U.S. Pat. No. 7,774,896 hereafter called Patent Document 2) and a stationary power blower whose main body is fixed stationary in operation.