In this work, we present a new design involving a microheater-integrated quartz crystal microbalance (QCM) array for thermal desorption spectroscopy. Each QCM consists of two electrodes to excite thickness-shear-mode (TSM) vibrations on the crystal back side and one microheater to increase the temperature on the crystal front side. The resonance frequency was stable when a voltage was applied to the microheater. Carbon microparticles were coated on one of the QCMs for gas adsorption, and its frequency change during the temperature increase was calculated by subtracting the frequency change of an untreated QCM. The proposed QCM array was employed to separate ethanol from methanol. The separation was successful, as confirmed via thermal desorption spectra calculated by differentiating the resonance frequency change with respect to time.