An object is to provide a micro-bubble generator, etc., capable of efficiently generating bubbles having a particle size of a nanometer order. One aspect of the present invention is a micro-bubble generator provided with a swirl chamber, a fluid introduction opening connected to the swirl chamber, the fluid introduction opening for introducing fluid along a line tangent to an inner surface of the swirl chamber, and a discharge tube for guiding the fluid in the direction substantially perpendicular to the direction in which the fluid is introduced. The discharge tube penetrates a wall surface of the swirl chamber and protrudes to an interior of the swirl chamber. According to the present configuration, by isolating a path of the introduced fluid, a loss of kinetic energy of a swirl flow of the fluid can be reduced. Thus, the micro-bubble generator capable of reducing the size of the generated micro-bubbles can be obtained.
