A cleaning agent composition which contains as major components an aminodicarboxylic acid N,N-diacetic acid salt, (particularly aspartic acid N,N-diacetic acid salt or glutamic acid N,N-diacetic acid salt) and a glycolic acid salt and of which a cleaning liquid has pH 8.5 or higher. Preferably, the composition further contains anionic surfactant and/or nonionic surfactant or an alkali metal hydroxide.The cleaning agent composition of the present invention has excellent cleaning effect and biodegradability and can be used advantageously as domestic, medical, and industrial cleaning agents.