An alkyloxirane derivative represented by formula (1), wherein MH and ML calculated from a gel permeation chromatogram satisfy formula (2):Z—；[O-(AO)n-H]x ； ；(1)where Z represents a residual group of a compound having 1 to 22 carbon atoms and one to six hydroxyl groups and wherein all of the hydroxyl groups are excluded from said compound； x is 1 to 6； and AO represents an oxyalkylene group having 3 carbon atoms； and n is 25 or more；0.35≤；ML/MH≤；0.75 ； ；(2)where MH represents a distance between point O and intersecting point P, and ML represents a distance between point Q and intersecting point P determined from the chromatogram.
