A bacterium belonging to the genus Erythrobacter which can produce adonixanthin accounting for 35% by mass or more and astaxanthin accounting for 5% by mass or more, of the produced composition； a bacterium of Erythrobacter JPCC O sp. whose 16S rDNA sequence consists of the nucleotide sequence represented by SEQ ID NO:1 or a nucleotide sequence having a 96% or higher homology with the nucleotide sequence represented by SEQ ID NO:1； a bacterial culture product yielded by culturing the bacterium； an astaxanthin-containing composition collected from the bacterium； and a method for producing astaxanthin which comprises the step of culturing the bacterium.
