The present invention provides a method for producing a pyrimidinylpyrazole compound (1), wherein aminoguanidine (2) or its salt is reacted with a β-diketone compound (3) to produce the pyrimidinylpyrazole compound: wherein R1 and R3 are each independently an alkyl group having 1 to 4 carbon atoms, and R2 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. The method is excellent in the environmental compatibility and economic efficiency.