The present invention relates to a new alga having an improved ability to produce a pigment, and when a mutant of the present invention is used, a carotenoid-based pigment, specifically, a xanthophyll can be produced by consuming less energy, so that it is possible to efficiently produce the pigment at the industrial level. Further, the pigment can be applied as a raw material for a food, a health functional food and a medicine, which include the pigment. In particular, since a DNA fragment is not likely to be inserted into a target base sequence or a base sequence other than the target, it is expected that the procedure of constructing the mutant is not regulated as a GMO, so that it is expected that the procedure of constructing the mutant can create a big economic effect in terms of an industry which produces lutein and zeaxanthin by using microalgae.