The invention relates to an automatic glass thickness adjusting device of a glass washer. The automatic glass thickness adjusting device is characterized in that an existing adjusting screw of equipment is demounted, a spring support is added in an adjusting screw sliding way, and a tension spring of 16mm and 180mm is arranged according to a thickness adjusting range of the glass washer, wherein the adjusting range refers to raw sheet glass of 0-20mm in thickness; for the glass washer exceeding the range through theoretical calculation, the tension spring is arranged in a manner that diameter of the tension spring is increased by 0.8mm correspondingly each time glass thickness is increased by 1mm according to experience number verified in production practice, and length of the tension spring is increased by 9mm correspondingly. Raw sheet glass different in thickness is compressed automatically through counteracting force of the tension spring during feeding, requirements on tension of the existing adjusting screw are met, and automatic adjusting of feeding of the raw sheet glass different in thickness is realized.