Sensor device

A sensor device comprising:

• a first electrode including a porous body that has a plurality of holes in at least the vicinity of a surface of the first electrode, the first electrode including a first metallic material in which either a first passivation film is formed on the surface of the first electrode or the first passivation film present on the surface of the first electrode is lost;
• a second electrode spaced apart from the first electrode, the second electrode including a porous body that has a plurality of holes in at least the vicinity of a surface of the second electrode;
• and
• a functional element configured to measure a difference in electric potential between the first electrode and the second electrode,
• a porosity of the first electrode and a porosity of the second electrode being different from each other,
• the sensor device being configured to measure a state of a site to be measured based on the difference in electric potential as measured by the functional element.