Provided is a gas detection device used in a humid environment such as a kitchen or a cooking room, which is excellent in moisture resistance and also excellent in sensitivity. In a gas detection device which includes a thin film type gas sensor including a heater portion, a gas detection portion, and a catalyst portion on a substrate, energizes the heater portion to heat the gas detection portion and the catalyst portion, and detects the detection target gas, the gas sensor configured by supporting a catalyst metal containing platinum as a main component on a support containing a transition metal oxide as a main component is adopted.