PURPOSE: To provide a process for producing partial oxidation products of methanol such as formaldehyde, methyl formate and dimethoxymethane from methanol and oxygen using a novel catalyst comprising an ion conductor and at least two different kinds of metal components.

CONSTITUTION: A mixture of methanol and oxygen is brought into contact with a novel catalyst comprising a combination of a proton conductor and 2 or more different kinds of metals to produce the partial oxidation products of methanol. Particularly, a combination of rhodium with iridium is preferably used and they are mixed with an ionic conductor containing a carbonaceous substance and phosphoric acid and the resultant catalyst is used to enable efficient production of the partial oxidation products of methanol.