NOVELTY - The hydrogen selenide mixed gas is supplied by adjusting concentration of hydrogen selenide mixed gas to predetermined value by mixing an inert gas supplied from base-gas supply flow path (L1), and hydrogen selenide mixed gas (100%) is supplied from a source-gas supply flow path (L2). The base-gas supply flow path and source-gas supply flow path are mutually connected by a bypass flow path (L7). The inert gas is drawn from the source-gas supply flow path through the bypass flow path, after drawing selenide mixed gas (100%) from the source-gas supply flow path.    USE - Supply of hydrogen selenide mixed gas used for solar cell.    ADVANTAGE - The method enables stable supply of hydrogen selenide mixed gas. The autolysis of hydrogen selenide mixed gas is suppressed. The precipitation of selenium crystals in the source-gas supply flow path is reduced.    DETAILED DESCRIPTION - The hydrogen selenide mixed gas is supplied by adjusting concentration of hydrogen selenide mixed gas to predetermined value by mixing an inert gas supplied from base-gas supply flow path, and hydrogen selenide mixed gas (100%) is supplied from a source-gas supply flow path. The base-gas supply flow path and source-gas supply flow path are mutually connected by a bypass flow path. The inert gas is drawn from the source-gas supply flow path through the bypass flow path, after drawing selenide mixed gas (100%) from the source-gas supply flow path. The concentration of hydrogen selenide mixed gas in the source-gas supply flow path is 10 vol.% or less. An INDEPENDENT CLAIM is included for apparatus (1) for supplying hydrogen selenide mixed gas.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic view of the apparatus for supplying hydrogen selenide mixed gas. (Drawing includes non-English language text)    Apparatus for supplying hydrogen selenide mixed gas (1)    Mixed gas storage tank (2)    Base-gas supply flow path (L1)    Source-gas supply flow path (L2)    Bypass flow path (L7)