A glow plug includes a housing having an axial hold and provided with a screw portion, and a heater member inserted into the axial hole. The housing includes a front-end-side body portion extending to the front end side from a front end of the screw portion, and a gasket portion lying adjacent to a front end side of the front-end-side body portion and bent at a bent portion provided at a rear end thereof so that at least a rear end portion thereof extends in a direction intersecting a direction of an axis. The gasket portion includes a pressure contact portion in which a surface thereof located at an outer circumferential side is brought into pressure contact with a seat surface of an internal combustion engine when the screw portion is screwed into a mounting hole in the internal combustion engine.