The utility model discloses a device to use Halymenia microcarpa to produce a high absorbance of phycoerythrobilin and comprises a first culture channel, a second culture channel, a collector, a grinder, an agitator and a precipitator. Utilizing the life history of Halymenia microcarpa carrying the character of three alternation of generations of sexual reproduction, asexual reproduction and vegetative reproduction and a variety of mucus no existent at the stage of carpospore filament, under a controlled ray, temperature and nutrition condition, the utility model can extend the stage of carpospore filament and further utilize the Halymenia microcarpa as the raw material to extract a high absorbance of phycoerythrobilin. The utility model depends on a high specific value of mass of phycoerythrobilin at unit mass of Halymenia microcarpa to lower the unit production cost and reduce the purification procedure of phycoerythrobilin.