A sheathed thermocouple includes thermocouple wires; a metal sheath accommodating the thermocouple wires; inorganic insulating material powder filled in an internal space of the metal sheath; a glass seal part tightly sealing an opening of the metal sheath while allowing the thermocouple wires to pass; compensation lead wires connected to the thermocouple wires; a metal sleeve having a cylindrical shape having a leading end part defining a connecting section connected with an outer peripheral surface of the metal sheath, and allowing a portion of the metal sheath closer to a proximal end than the connecting section, the thermocouple wires and the compensation lead wires to be in an internal space, the thermocouple wires and the compensation lead wires lying without contact between themselves; and a glass filler part made of a glass having a lower softening temperature than the glass seal part, and filling an internal space of the metal sleeve.