PROBLEM TO BE SOLVED: To provide an apparatus for producing microbubbles by which energy necessary for producing the bubbles can be reduced, machining for manufacturing the apparatus is easy and thereby the apparatus can be manufactured at a low cost and size of the bubble can be easily adjusted. SOLUTION: The apparatus for producing the microbubbles is constituted of a pipe for supplying pressurized water and discharging it together with self- absorbed air, a spherical body which is located at an intermediate part of the pipe and is inserted in the pipe, small holes provided by boring on a periphery of the pipe at the downstream from an insertion center of the spherical body and an air chamber which is provided at the outside of the small hole and communicates with the outside air. COPYRIGHT: (C)2004,JPO