According to the present invention, a process for manufacturing alkali metal salt of clavulanic acid wherein impure clavulanic acid in aqueous solution is extracted by a solvent mixture of ketone and alkyl acetate under acidic condition, treated in a conventional manner, and a solution of alkali metal salt of alkanoic acid dissolved in ketone or alkanol solvent is added to obtain pure alkali metal salt of clavulanic acid is provided. Since the process according to the present invention omits a step of formation of amine salt, an economic and simple method for manufacturing alkali metal salt of clavulanic acid in a high yield without excessive use of solvent is provided.