A glass antenna device having an AM and FM antennas provided on a rear window glass panel on which a defogger is formed is provided, the sensitivity and directivity of the device being improved. The device comprises a defogger provided on a rear window glass panel of the motor vehicle, an AM antenna provided in a space other than the defogger on the rear window glass panel, an FM antenna provided in a space between the defogger and the AM antenna on the rear window glass panel, a two-input amplifier for amplifying signals received by the AM and FM antennas, an AM lead wire for connecting between a feeding terminal of the AM antenna and the amplifier, an FM lead wire for connecting between a feeding terminal of the FM antenna and the amplifier, and an inductor inserted in the AM lead wire near to the AM feeding terminal.