Abstract: Efficiency of production method for producing astaxanthin by culturing microalgae is improved. A method for producing astaxanthin in which astaxanthin is produced in inner of algae by culturing a microalga, wherein a light irradiation during a green stage culturing of the microalga is performed by using both a blue LED of peak wavelength from 420 to 500 nm and a red LED of peak wavelength from 620 to 690 nm, and having a ratio of photon flux density of the blue LED to the red LED to be 2:3 to 20:1. It is preferable that the photon flux density of the blue LED is from 5 to 200 ?mol/m2/s, and the photon flux density of the red LED is from 5 to 200 ?mol/m2/s.

Abstract: A method for increasing efficiency of a method for producing astaxanthin by culturing a microalga. A method for producing astaxanthin in which astaxanthin is produced in an algal body by culturing a microalga, wherein photoirradiation is performed using both a blue LED of peak wavelength from 420 to 500 nm and a red LED of peak wavelength from 620 to 690 nm, at least during an astaxanthin-producing culturing phase of a culturing period. The ratio of the blue LED of peak wavelength from 420 to 500 nm and the red LED of peak wavelength from 620 to 690 nm is preferably from 1:19 to 19:1 by photon flux density, and the photon flux densities are each preferably not less than 20 ?mol/m2/s.