To provide a new water-based asymmetric Michael reaction process making the best use of a reaction process using a Lewis acid catalyst in an aqueous solvent and also enabling a Michael addition compound to be selectivity synthesized in high yield and high asymmetry.

This water-based asymmetric Michael reaction process comprises reaction between a β-ketoester compound and an α,β-unsaturated ketone in an aqueous solvent in the presence of a chiral silver catalyst.