NOVELTY - The apparatus has a reactor (11) into which hydrogen and metal selenium are injected through a hydrogen injection path (12) and a metal selenium injection path (13). The reactive gas containing gaseous hydrogen selenide produced by reactor is extracted through a reactive-gas extraction path (14). A selenization hydrogen collecting apparatus (15) is configured to collect hydrogen selenide in extracted reactive gas. A gas circulation path (17) is provided to extract reactive gas from selenization hydrogen collecting apparatus, and to return extracted gas to hydrogen injection path.    USE - Apparatus for producing selenization hydrogen used during manufacture of solar cell such as copper indium selenide (CIS) type solar cell and copper zinc tin sulfide (CZTS) type solar cell.    ADVANTAGE - Since hydrogen in reactive gas can be effectively utilized as a raw material by returning the reactive gas after collecting hydrogen selenide with the selenization hydrogen collecting apparatus, the effective usage of a metal selenium or hydrogen can be aimed. Hence hydrogen selenide can be manufactured continuously while improving the yield. The energy for carrying out heating and cooling operation of reactor can be reduced. Since unreacted metal selenium in the reactive gas can be extracted from the reactor and is re-decomposed, the hydrogen selenide can be obtained easily. The obstruction in metal selenium injection path due to metal selenium precipitation can be prevented.    DETAILED DESCRIPTION - The heating coolers (16a,16b) are provided to heat the hydrogen supplied to reactor and to cool the reactive gas extracted from reactor. A relay container (30) and a metal selenium injection container (29) are provided in series with metal selenium injection path. The opening-and-closing units (31-33) are provided between metal selenium injection container and relay container and between relay container and reactor. The purge paths (35a,35b) for substituting the gas in metal selenium injection container are provided. A metal selenium refinement unit is provided to remove the impurity contained in metal selenium and to circulate the gas for refinement.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic view of the selenization hydrogen production apparatus.    Reactor (11)    Hydrogen injection path (12)    Metal selenium injection path (13)    Reactive-gas extraction path (14)    Selenization hydrogen collecting apparatus (15)    Heating coolers (16a,16b)    Gas circulation path (17)    Metal selenium injection container (29)    Relay container (30)    Opening-and-closing units (31-33)    Purge paths (35a,35b)