Abstract: An apparatus for culturing microalgae is characterized by comprising:(1) a waterway a to be filled with a suspension containing a culture solution and microalgae and adapted to be irradiated with sun beams while being held in contact with ambient air;(2) an upper hermetically sealed storage tank b for storing said suspension to avoid any contact between the latter and ambient air, said storage tank being provided with a deaeration and a switch valve;(3) an aeration pipe c arranged and apertured in the storage tank b for feeding pressurized gas into the storage tank b; and(4) a pressurized gas feeder d;the upstream end and the downstream end of the waterway a and the storage tank b being linked at the bottom of the storage tank b by way of a water conduit f to form an endless waterway; the upstream end and the downstream end of the waterway a and the storage tank b being linked at the bottom of the storage tank b so as to allow pressurized gas fed through the aeration pipe c to burst out from the bottom of the