Abstract: A substrate is disposed in a reactor kept to be a vacuum state, a material gas is supplied into a space in front of the substrate, high-frequency electric power is supplied to the material gas to generate plasma based on electric discharge excitation in the front space of the substrate, and an amorphous silicon thin film is deposited on the substrate by chemical vapour deposition. Further, an electrode section comprising tubular electrodes supplying the material gas through a plurality of gas discharge openings, and tubular electrode sucking and evacuating gases to the outside through a plurality of gas suction openings. Thereby, a higher silane gas and the like generated during the film deposition can be removed from a reactive region immediately, and a thin film is deposited on the substrate surface with the same condition of the film deposition at any spot of the substrate surface. Consequently, the amorphous silicon thin film with film quality may be deposited on the large-area substrate.