A new alga having an improved ability to produce a pigment is disclosed. When the alga 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. The pigment can be applied as a raw material for a food, a health functional food and a medicine, which include the pigment. 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.
