To provide a method of purifying polyglyceline-type surfactant which enables to obtain a high quality polyglyceline surfactant by efficiently removing hydrophobic impurities which markedly lower the surface activity performance.

The method of purifying polyglyceline-type surfactnt is characterised in that, after water, the polyglyceline-type surfactant, and a polyoxyalkylene compound expressed by the formula: R1-O-(AO)m-R2 (I) are mixed, the water phase containing the polyglyceline-type surfactant and the phase containing the polyoxyalkylene compound are mutually separated. In the formula, each of R1 and R2 shows a 1-24C alkyl group or acyl group, AO shows a 2-4C oxyalkylene group, but 50 mol% or more of the AO is a 4C oxyalkylene group, and m shows a number of 3 to 25.