Method for producing gas sensor element, gas sensor element, and gas sensor

A method for producing a gas sensor element extending in a direction of an axial line thereof and having a detection portion disposed on a front end side thereof, the detection portion being covered by, as a porous protection layer, an inner protection layer that is porous and an outer protection layer that is porous and that has a porosity different from a porosity of the inner protection layer, in this order, the method comprising:

• a first dipping step of dipping the front end side of the gas sensor element into a first slurry for the inner protection layer, to form a first coating film made of the first slurry on a front end surface and a peripheral surface of the gas sensor element;
• a drying step of drying and solidifying the first coating film;
• a second dipping step of dipping, without removing the first coating film, the front end side of the gas sensor element into a second slurry for the outer protection layer, to form a second coating film made of the second slurry on an entirety of a surface of the solidified first coating film;
• and
• a scraping-off step of performing scraping-off on the second coating film so as not to scrape-off the solidified first coating film, to remove a part of the second coating film.