Sensor element and gas sensor

A sensor element for detecting a concentration of a specific gas in a measurement gas, the sensor element comprising:

• an element body having an oxygen-ion-conductive solid electrolyte layer and having formed therein a measurement gas flow path and a reference gas chamber, the measurement gas flow path being a path into and through which the measurement gas is introduced and flows, the reference gas chamber being a chamber in which a reference gas used as a reference to detect the concentration of the specific gas in the measurement gas is to be stored;
• a first pump cell having a first pump electrode disposed at a portion of the element body that comes into contact with the measurement gas, and a first reference electrode disposed in the reference gas chamber, the first pump cell being configured to pump oxygen from around the first pump electrode to around the first reference electrode;
• a first connector electrode disposed on an outer surface of the element body;
• and
• a first inner lead portion disposed inside the element body, connected to the first reference electrode, and configured to electrically connect the first connector electrode and the first reference electrode;
• wherein the first inner lead portion has a reference gas flow region that is porous and constitutes at least part of a reference gas flow path allowing the reference gas to flow between the reference gas chamber and an outside of the element body;
• and
• wherein a limiting current A when oxygen is pumped out from around the first reference electrode to around the first pump electrode is 1.5 μA or more.