To provide a catalyst enabling both triethylenediamines and piperazines to be produced in a high yield and stably for a long time, and also to provide a production method using the same catalyst.

This method for producing both triethylenediamines and piperazines comprises catalytically reacting an amine compound of the formula, wherein R1 to R4 are each H or a (substituted)1-3C alkyl in the presence of a crystalline aluminosilicate having a molar ratio of (alumina/silica) of ≥12. The crystalline aluminosilicate is obtained by baking an aluminosilicate at 500-950°C and then by subjecting the baked product to catalytic treatment with an inorganic acid and is a pentasil-type aluminosilicate, and preferably has an molar ratio of (alumina/silica) of 40-5,000. The inorganic acid is at least one kind selected from the group consisting of hydrogen chloride, hydrogen bromide, sulfuric acid, nitric acid and perchloric acid.