Abstract: A monoalkylether of dihydric phenol compound is produced by bringing a feed gas comprising a mixture gas of a dihydric phenol compound with a monohydric alcohol compound into contact with an active catalyst component comprising at least one member selected from phosphorus compounds, and mixtures and reaction products of phosphorus compounds with boron compounds and carried on an inert solid carrier consisting of, for example, .alpha.-alumina, .gamma.-alumina, activated carbon or titania grains, and preferably having a pore volume of 0.1 ml/g or more and a specific surface area of 1 m.sup.2 /g or more, at a temperature of 200.degree. C. to 400.degree. C., and collecting the resultant reaction product from the reaction mixture.