To provide a method for producing hydrogen by micro alga for effectively producing the hydrogen by the culture of green alga of the genus Chlamydomonas.

The method for producing the hydrogen by the micro alga comprises preparing a medium of a culture solution obtained by reducing the concentration of one component of phosphorus, nitrogen, iron, magnesium, manganese and copper in the culture solution such as TAP, or reducing both of the concentration of one of them and the concentration of a sulfur component, culturing the green alga of the genus Chlamydomonas by inoculating the green alga in the medium, and taking out the hydrogen from the generated gas in the medium.