PURPOSE: To obtain the sensor which has high accuracy of humidity detection and is stable by using a MIM element in a humidity detecting part.

CONSTITUTION: Ta is sputtered on a glass substrate 4. Ar is used for a sputtering gas and the sputtering is executed under 0.7 Pa sputtering gaseous pressure. The thickness of the formed Ta film is 3,000. The Ta is then patterned and etched to 5μm width by dry etching in a CF4+O2 atmosphere. This Ta is anodized by impressing 30V in an aq. 1% citric acid sol. The thickness of the anodized film is 600 when the film is analyzed by an elipsometer and IMA. Cr is then sputtered and is patterned to 5μm width by wet etching with ceric ammon sulfate. The Ta, TaOx and Cr are orthogonal with each other at this time. The MIM (Metal-Insulator-Metal) element is used in the humidity detecting part in such a manner. The insulator of the MIM element is formed by an anodic oxidation method.