Glassy carbon (GC) thin film was successfully deposited via thermal pyrolysis of ethanol vapor by means of chemical vapor deposition at 1000 °C without any catalysis. The Raman spectra of the grown GC film showed typical peaks of D1, G, and 2D1 including derivative peaks of D2 band and a combinational peak of D1 + G that indicates the film is glassy carbon. XPS analysis of the C 1s core showed the deposited films have carbon atoms consisting of an almost sp2 binding structure. A picture of the cross-sectional transmission electron microscope showed the stacking layers of a disordered carbon have a turbostratic layer with a few nanometers graphitic domain, about 13 nm estimated by Raman spectra. Two types of pH sensor were fabricated. One is a GC based field-effect transistor with a top gate of a solution (GC-FET), and the other is a GC extended gate electrode connected to commercial Si FET (GC-EGFET). The average pH sensitivity of GC-FET and GC-EGFET is 21.5 mV/pH and 26.5 mV/pH, respectively, which are comparable for graphene-based solution gating pH sensors that have appeared in the recent literature.