To provide a method for producing hydrogen with high energy conversion efficiency while suppressing cost.
The method for producing the hydrogen is carried out as follows. Organic wastes are biodegraded to provide degraded materials. Microalgae are made to conduct photosynthesis based on the degraded materials under bright aerobic conditions and the resultant photosynthetic product is then degraded with the microalgae under anaerobic conditions. Thereby, the hydrogen is simultaneously produced.