A heating device is constructed such that a heating member made of nickel-chromium or a high melting point metal is held in an electrically insulating member made of an oxide or nitride, and a solder connecting layer consisting of a nickel layer serving as buffer layer and a nickel plating layer serving as solder uniting layer is formed on a surface of the electrically insulating member corresponding to a slender portion of the heating member. An adhesion between the solder connecting layer and the electrically insulating member holding the heating member is thereby improved so that the heating device is achieved as having a high reliability and at the same time as capable of improving heat conducting performance from the heating member to a heated body.