To provide a method for industrially suitably producing a methoxy group-containing -diketone compound, which produces a methoxy group-containing -diketone compound by a simple method by using a safe alkylating agent.

The method for producing a methoxy group-containing -diketone compound comprises two processes of (A) a first process for reacting a halogenated carboxylic ester with a ketone compound and an alkali metal alkoxide to produce a halogenated -diketone compound and (B) a second process for reacting the halogenated -diketone compound with an alkali metal methoxide.