Abstract: A method for producing a gas sensor element, for covering a detection portion (150) by an inner protection layer (21) and an outer protection layer (22), including: a first dipping step of dipping the gas sensor element into a first slurry S1 for the inner protection layer, to form a first coating film (700) on a front end surface (100c) and a peripheral surface (100d); a drying step of drying and solidifying the first coating film; a second dipping step of dipping, without removing the first coating film, the gas sensor element into a second slurry S2 for the outer protection layer, to form a second coating film (800) on 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 first coating film, to remove a part of the second coating film.

Abstract: A fluid heating ceramic heater can suppress adhesion of scale to a surface of the ceramic heater over an extended time period, and efficiently conduct heat generated from a heat generation resistor to fluid. The ceramic heater has a ceramic body, an outer coating layer and an inner coating layer. The ceramic body has a heat generation resistor. The outer coating layer and the inner coating layer contain glass as a main component and coat a surface of the ceramic body. The outer coating layer and the inner coating layer are formed so that the inner coating layer is thinner than the outer coating layer.