A process for preparing polyether polyols by the addition polymerization of alkylene oxide to active hydrogen containing compounds in the presence of the amine catalyst represented by the following formula :
wherein R₁ is an alkyl group or an alkenyl group having from 8 to 20 carbon atoms and R₂ and R₃ are independently a hydrogen atom or an alkyl group having from 1 to 8 carbon atoms.
The polyether polyol obtained has a light hue, faint foreign odor and an excellent quality as a material for rigid polyurethane forms.