Provided is a sensor which enables detection/identification of various types of fuels for automobiles by using simple devices. According to the present invention, high-octane gas, regular gas, diesel oil, heating oil, gasoline laced with heating oil, and the like can be clearly identified without using a large-scale analysis such as gas chromatography or mass spectroscopy by using a sensor having a structure in which a surface of a sensor body which detects a surface stress or the like is coated with particles modified with a hydrocarbon group such as an alkyl group.