The present invention provides a method for efficiently producing a sulfonic acid group-containing ether compound having a high purity and a good polymerizability while preventing production of a byproduct, and provides a sulfonic acid group-containing ether compound containing fewer impurities and having a good radical (co)polymerizability.The present invention provides a method of producing a sulfonic acid group-containing ether compound by reacting a sulfurous acid compound with a compound represented by the formula (1): wherein R1 represents a single bond, a CH2 group, or a CH2CH2 group, and R2 represents H, or a CH3 group, the method comprising the steps of: adjusting pH of a reaction system to 5.5 or greater with use of an alkaline substance; and adding the compound represented by the formula (1) to a reaction vessel containing the sulfurous acid compound.