A glow plug (1) provided with heater (2); tubular main metal shell (4) with shaft hole (43); conductive member (3) extending in the shaft hole toward a rear end side GK; metal terminal member (5) with one part (55) positioned in the shaft hole and another part (56) protruding from a rear end (48) of the main metal shell toward the rear end side GK, the terminal member including an enclosing portion (51) opened toward a front end side GS housing a rear end portion (32) of the conductive member and having electrical continuity with the rear end portion, the terminal member being disposed in the shaft hole while spaced apart from an inner peripheral surface 43m of the main metal shell; and sealing member (7) made of an insulator and airtightly sealing and insulating between the inner peripheral surface and the terminal member in the shaft hole.