An extraction apparatus capable of continuously and efficiently extracting a biological substance is provided. Multiple rotation discs are utilized in the extraction apparatus to significantly improve the efficiency of extracting the biological substance by using an extraction solvent. Specifically, when the extraction solvent is applied to extract lipids from microalgae, retention time of the microalgae in the extraction solvent can be significantly increased, and solubility of the microalgal lipids in the extraction solvent can be improved. Hence, the efficiency of extracting the lipids from the microalgae by using the extraction solvent can be enhanced. On the other hand, owing to the improvement of the efficiency of extracting the lipids from the microalgae, the amount of the extraction solvent can be reduced, and production costs can be reduced as well.