PURPOSE: To improve a soldering property by using a silver containing material and also, not to short-circuit irreversibly by depositing the silver even if water is stuck to an element, by covering a terminal electrode of a dew condensation detecting element by an insulating and waterproofing thermosetting resin composite.

CONSTITUTION: Terminal electrodes 2, 2' are formed by printing electrically conductive paste essentially consisting of Pd and Ag on a ceramic insulating substrate 1 and calcining it and hereafter, a pair of electrode 3, 3' is formed by using the electrically conductive paste essentially consisting of ruthenium oxide. Next, the electrode 3 is connected with the electrode 3' and a porous hygroscopic humidity sensitive body 4 essentially consisting of barium titanate is formed and then, each lead wire 5, 5' is connected with each electrode 2, 2' by a solder 6. Next, a resin film 8 is formed by applying an insulating and waterproofing themosetting resin composite essentially consisting of epoxy resin which covers the electrodes 2, 2' and by hardening it. In this manner, an inexpensive and highly reliable dew condensation detecting element is obtained.