The effect of Si+ ion irradiation of α-Ga2O3 at doses of 8·1012 cm-2, 8·1014 cm-2, and energy of 100 keV on the gas-sensitive properties has been studied. It is shown that irradiation of α-Ga2O3 layer grown by halide vapor phase epitaxy with implanted Si+ ions allows effective control of its sensitivity to H2, response, and recovery times, as well as varying the operating temperatures. The maximum sensitivity to H2 occurred for samples with Si+ ion irradiation dose of 8·1012 cm-2 at 400ºC. The mechanism of sensitivity of α-Ga2O3 epitaxial layers irradiated with Si+ to H2 is discussed.