PROBLEM TO BE SOLVED: To obtain a large amount of algae at a low cost by laying the subject drift net type net used for culturing the algae and capable of corresponding to scale up, automation and labor saving on an ocean (lake or marsh), and subsequently culturing, harvesting and processing the algae. SOLUTION: This drift net type culture net (length: 3,000 m) is reasonably bound to inclined ropes in a block culture net width from a profitable deep sea (average depth: about 2,000 m) through an anchor, a rope and an adjustable ring, and has a structure in which plural blocks are laterally connected to each other. The drift net type culture net is used for culturing the algae and subsequently harvesting the cultured algae in the optimal cutting period, while leaving parent spore roots for next year culture (unevenly cropping the culture algae).
