NOVELTY - A hydrogen-selenide mixed gas supply apparatus (10) comprises a base gas supply line (12), selenization hydrogen gas supply tube (21), flow measurement device (26) and mixed gas generation tube (31) which is connected with base gas supply line and selenization hydrogen gas supply tube, in which the base gas and the selenization hydrogen gas are mixed. The internal diameter of the tubular component (58) of flow measurement device is set so that the fluctuation of the flow volume of the selenization hydrogen gas that flows through the tubular component is in predetermined range.    USE - Hydrogen-selenide mixed gas supply apparatus is used in manufacture of compound solar cell.    ADVANTAGE - The hydrogen-selenide mixed gas supply apparatus provides stable supply of hydrogen-selenide mixed gas with respect to the consumption destination.    DETAILED DESCRIPTION - A hydrogen-selenide mixed gas supply apparatus comprises a base gas supply line which supplies the base gas by which flow volume is controlled, selenization hydrogen gas supply tube which supplies selenization hydrogen gas, flow measurement device which measures the flow volume of the selenization hydrogen gas which flows through the selenization hydrogen gas supply tube, flow-control portion (25) which controls flow volume based on the flow volume of the selenization hydrogen gas which is provided in the selenization hydrogen gas supply tube, and mixed gas generation tube which is connected with base gas supply line and selenization hydrogen gas supply tube, in which the base gas and the selenization hydrogen gas are mixed, and the concentration of the mixed gas is set at predetermined concentration. The flow measurement device comprises tubular component, in which one end is connected with the selenization hydrogen gas supply tube located in the upstream of the flow measurement device, and the other end is connected with the selenization hydrogen gas supply tube located in the downstream of the flow measurement device. In the tubular component, the increase rate in crystal occupation rate is calculated based on the cross-sectional area of tubular component in direction perpendicular to the plane with respect to the extending direction of the tubular component, and the occupancy cross-sectional area in the surface direction of the selenium crystallized in the tubular component per unit time, for a predetermined period. The internal diameter of the tubular component is set so that the fluctuation of the flow volume of the selenization hydrogen gas that flows through the tubular component is in predetermined range.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of hydrogen-selenide mixed gas supply apparatus. (Drawing includes non-English language text)    Hydrogen-selenide mixed gas supply apparatus (10)    Base gas supply line (12)    Selenization hydrogen gas supply tube (21)    Flow control portion (25)    Flow measurement device (26)    Mixed gas generation tube (31)    Buffer tank (33)    Tubular component (58)    Vibration generation portion (61)