A hydrogen system includes: a water electrolysis apparatus including a water electrolysis cell; an electrochemical hydrogen pump that increases the pressure of hydrogen-containing gas produced by the water electrolysis apparatus; a gas flow path that supplies the hydrogen-containing gas produced by the water electrolysis apparatus to the electrochemical hydrogen pump; and a first flow path through which a first heat medium that is a liquid and has collected waste heat of the water electrolysis cell flows. The electrochemical hydrogen pump is capable of performing heat exchange with the first heat medium having collected waste heat of the water electrolysis cell.