PURPOSE: To reutilize a microbial cell without its breakage and reduce the production cost of a pigment by culturing microalgae to a stationary phase, then reacting the resultant recovered microbial cell with a tertiary amine and extracellularly secreting the red pigment.

CONSTITUTION: Microalgae (preferably halophilic microalgae of the genus Platymonas) are cultured to a stationary phase to sufficiently accumulate a red pigment in the algal body. A tertiary amine is then made to react with the live algal body to extracellularly secrete the resultant red pigment. The treatment with the tertiary amine is carried out by, e.g. a method for immersing the algal body in a solution of the tertiary amine. Furthermore, N,N-bis (2- hydroxyethyl)glycine and N-2-hydroxypiperazine-N'-2-ethanesulfonic ac id are preferred as the tertiary amine.