The invention relates to the preparation of oyster flesh extracts. Raw oyster flesh is placed in an extractor with a solution stored in it. The extractor is closed up tight and pressurized to 1 atm or higher to extract oyster flesh extracts from the raw oyster flesh, and they are fed into the solution in the extractor. An extraction solution with the oyster flesh extracts fed in it is concentrated. An alcohol solution is added to the concentrated solution to precipitate out the oyster flesh extracts. The precipitates are dried into dry oyster flesh extracts.