A shower head includes a gas injection plate and a gas supply unit. The gas supply unit has a first gas supply path provided in a region along the axis and a second gas supply path provided in a region surrounding the region where the first gas supply path is provided. The first gas supply path has a first gas diffusion space connected to a first gas line of the gas supply unit, second gas lines, a second gas diffusion space, third gas lines and a third gas diffusion space which are connected in that order. The second gas supply path has a fourth gas diffusion space connected to a fourth gas line of the gas supply unit, fifth gas lines, a fifth gas diffusion space, sixth gas lines, and a sixth gas diffusion space which are connected in that order.