Disclosed is a pressure sensor that outputs a temperature change caused in an electrical resistor according to a pressure of a gas, as a resistance change in the electrical resistor. The pressure sensor includes: a base substrate including a recess formed therein, a floating film formed on the base substrate, a heater formed on a surface of the floating film and configured to heat the floating film when a current flows therein, and a temperature sensor formed as the electrical resistor on the surface of the floating film. The temperature sensor changes a voltage drop with respect to a current flowing therein according to the temperature of the floating film.