The present invention is directed to provide a catalyst for reduction, which is capable of reducing even mono-substituted alkynes to alkenes and does not require the coexistence (combined use) of a toxic compound, and a method for reduction from alkynes to alkenes using the catalyst; and relates to a palladium-supported polyethyleneimine compound obtained by contacting a polyethyleneimine, a palladium compound and hydrogen gas in an oxygen-free state, a method for producing the above palladium-supported polethyleneimine compound, a catalyst for reduction comprising the above palladium-supported polyethyleneimine compound, and a method for reducing from alkynes to alkenes characterized by contacting an alkyne and hydrogen in the presence of a palladium-supported polyethyleneimine compound, which is obtained by reacting a polyethyleneimine, a palladium compound and hydrogen gas in an oxygen-tree state.