A glass antenna device for an automobile which has an electric heating type defogger, antenna conductors disposed near the defogger in a capacitive coupling relation, which are formed on a glass sheet to be fitted to a rear window opening of an automobile, and a reactance circuit connected between bus bars for the defogger and a d.c. power source for the defogger, wherein there is an anti-resonance point caused by impedance composed mainly of capacitance which is produced in correlation among the antenna conductors, the defogger and the body of automobile and the impedance of the reactance circuit, the anti-resonance point being out a predetermined receiving frequency band region or a predetermined broadcast frequency band region, and there is a resonance point between the frequency of 1.5 times of f.sub.H and f.sub.L, where f.sub.H is the highest frequency in the predetermined receiving frequency band region or the predetermined broadcast frequency band region and f.sub.L is the lowest frequency of the same, which is caused by the impedance of a predetermined circuit connected between a power feeding terminal for the antenna conductors and a receiver; the input impedance of the receiver and the impedance of the antenna conductor side viewed from the predetermined circuit.