PROBLEM TO BE SOLVED: To provide an exhalation sensor that measures a flow rate, a temperature and humidity of exhalation by using a single-element sensor to determine whether it is exhalation of a person or not, and an alcohol concentration measuring device using the same.SOLUTION: An exhalation sensor includes: a first temperature-sensitive resistor 31 and second temperature-sensitive resistor 32 that are provided on one semiconductor substrate 2 and arranged in an exhalation flow path a first circuit that controls the first temperature-sensitive resistor to be at a first temperature and outputs the amount of power corresponding to power consumption for maintaining it at the temperature a second circuit that controls the first temperature-sensitive resistor to be at a second temperature and outputs the amount of power corresponding to power consumption for maintaining it at the temperature a third circuit that outputs the amount of power corresponding to a resistor value of the second temperature-sensitive resistor having almost the same temperature as a gas to be inspected and a fourth circuit that controls the temperature of the first temperature-sensitive resistor to be at a fourth temperature that is higher than that of the second temperature-sensitive resistor by a predetermined temperature, and outputs the amount of power corresponding to power consumption for maintaining it at the temperature.COPYRIGHT: (C)2014,JPO&INPIT【課題】単一素子のセンサにより呼気の流量及び温湿度を測定し、人の呼気であるか否かを判断する呼気センサ及びそれを用いたアルコール濃度測定装置を提供する。【解決手段】呼気センサは、1つの半導体基板2に設けられ呼気の流路中に設置される第1感温抵抗体31及び第2感温抵抗体32と、第1感温抵抗体を第1温度に制御し且つその温度に保つための消費電力に対応する電気量を出力する第1回路と、第1感温抵抗体を第2温度に制御し且つその温度に保つための消費電力に対応する電気量を出力する第2回路と、被検ガスと略同一温度の第2感温抵抗体の抵抗値に対応する電気量を出力する第3回路と、第1感温抵抗体の温度を第2感温抵抗体に対して所定温度だけ高い第4温度に制御し且つその温度に保つための消費電力に対応する電気量を出力する第4回路と、を備える。【選択図】図3
