A hydrogen production device comprising: a translucent substrate; a photoelectric conversion part having a light acceptance surface and a back surface, and provided on the translucent substrate; a first gas generation part provided on the back surface; and a second gas generation part provided on the back surface; a plate provided over the first gas generation part and the second gas generation part so as to be opposed to the substrate; a space is provided between each of the first gas generation part and the second gas generation part, and the plate; a second electrode provided between the back surface of the photoelectric conversion part and the first gas generation part; and a partition wall to separate a space between the first gas generation part and the plate and a space between the second gas generation part and the plate, wherein one of the first gas generation part and the second gas generation part is a hydrogen generation part to generate H 2 from an electrolytic solution, and another one thereof is an oxygen generation part to generate O 2 from the electrolytic solution, and the first gas generation part is electrically connected to the back surface, and the second gas generation part is electrically connected to the light acceptance surface via a first conductive part. the second gas generation part is provided on the back surface of the photoelectric conversion part via an insulation part, the first conductive part includes a first electrode being in contact with the light acceptance surface, and a second conductive part being in contact with each of the first electrode and the second gas generation part, and the partition wall is provided so as to leave a space between the plate and the partition wall, the space eliminating an imbalance in proton concentration. a translucent substrate; a photoelectric conversion part having a light acceptance surface and a back surface, and provided on the translucent substrate; a first gas generation part provided on the back surface; and a second gas generation part provided on the back surface; a plate provided over the first gas generation part and the second gas generation part so as to be opposed to the substrate; a space is provided between each of the first gas generation part and the second gas generation part, and the plate; a second electrode provided between the back surface of the photoelectric conversion part and the first gas generation part; and a partition wall to separate a space between the first gas generation part and the plate and a space between the second gas generation part and the plate, wherein one of the first gas generation part and the second gas generation part is a hydrogen generation part to generate H 2 from an electrolytic solution, and another one thereof is an oxygen generation part to generate O 2 from the electrolytic solution, and the first gas generation part is electrically connected to the back surface, and the second gas generation part is electrically connected to the light acceptance surface via a first conductive part. the second gas generation part is provided on the back surface of the photoelectric conversion part via an insulation part, the first conductive part includes a first electrode being in contact with the light acceptance surface, and a second conductive part being in contact with each of the first electrode and the second gas generation part, and the partition wall is provided so as to leave a space between the plate and the partition wall, the space eliminating an imbalance in proton concentration.