A method for producing a narrow molecular weight distribution polyalkylene glycol derivative having an amino group at an end is provided and allows for polymerization of ethylene oxide under mild conditions with suppressed occurrence of diol polymer impurities includes at least the steps of polymerizing ethylene oxide by using a compound represented by the following general formula (2) and converting a polymer end to R3: wherein R1 represents a linear, branched, or cyclic monovalent hydrocarbon group having 1 to 10 carbon atoms; R2 represents a linear or branched divalent hydrocarbon group having 1 to 5 carbon atoms; R3 represents a linear, branched, or cyclic monovalent hydrocarbon group having 1 to 20 carbon atoms; M represents sodium or potassium; m represents an integer of 1 to 5; n represents an integer of 1 to 450; and k represents an integer of 1 to 5.