The present invention provides an apparatus for generating microbubbles, the apparatus including a pressure tank (10) including an inlet port and an outlet port, provided at the top and bottom, respectively, and having a predetermined space therein; a fluid supply pump (11 ) for supplying a fluid to be treated to the pressure tank (10); a gas supply means (19) for supplying gas to the pressure tank (10); an injection means (12, 13) connected to the top of the pressure tank and injecting the fluid supplied from the fluid supply pump (11 ) to generate a head and a swirl flow of the fluid so that the gas is dissolved in the fluid and then a centripetal spiral motion of the fluid is created; and a bubble water ejecting (28) means for converting the fluid, discharged through the outlet port of the pressure tank (10) and activated by the centripetal spiral motion, into bubble water containing highly-concentrated microbubbles and discharging the bubble water.