A process for producing a titanium-containing silicon oxide catalyst, which comprises the following steps A and B; a catalyst obtainable by the process; and a process for producing an olefin oxide using the catalyst. Step(A) in which a silica source part or all of which is a silicon compound having a silicon atom having a hydrocarbon group directly bonded thereto is mixed by stirring with a titanium source and a template solution to obtain a solid containing the catalyst component and template, the rate of water in the solvent in the template solution being 50% by weight or lower or a step in which a silica source which comprises a combination of an organic silica source comprising a silicon compound having a silicon atom having a hydrocarbon group directly bonded thereto with a silicon compound having no carbon-silicon bond is mixed by stirring with a titanium source and the template solution to obtain a solid containing the catalyst component and the template, the addition of the silica source to the template solution being conducted so as to satisfy the relationship: (amount of the organic silica source added in the first half)>(amount of the organic silica source added in the latter half). Step B: a step in which the template is removed from the solid obtained in the step A.