The present invention aims to provide a method of producing a polyether polyol having a low aldehyde content, the method including simpler steps; and a method of producing polyurethane foam having a reduced amount of aldehyde volatilization. The present invention provides a method of producing a polyether polyol (F) including step (1) of obtaining a crude polyether polyol composition (D2) having a pH higher than 5.0 by contact of a crude polyether polyol composition (D1) containing a polyether polyol (A) with an acid catalyst (B) in the presence of water, the polyether polyol (A) being obtainable by ring-opening polymerization of an alkylene oxide with an active hydrogen compound; and step (2) of removing a volatile component containing an aldehyde (C) after step (1).