Glow plug comprising: - a hollow plug body extending along a longitudinal axis and having a proximal end and a distal end along the longitudinal axis; - a heating rod: • having at least one distal portion extending axially and projecting from the distal end of the plug body; and • having a proximal end equipped with at least one connector for supplying the heating rod with electricity; - at least one electrical connector, called the external connector, which: • projects axially from the proximal end of the plug body; and • is adapted to be capable of having a cable for supplying the glow plug with electricity connected to it; - a first, rigid, electrically conductive rod, called the distal rod, which is connected electrically, by a distal end, to at least one connector for supplying the heating rod with electricity; - a second, rigid, electrically conductive rod, called the proximal rod, which: • extends at least partially within the plug body; • is connected electrically, by a proximal end, to at least one external connector; and • is connected electrically, by a distal end, to a proximal end of the distal rod; characterised in that the glow plug also comprises an electrically insulating tubular sleeve which is mounted: - around the distal end of the proximal rod and the proximal end of the distal rod so as to clamp at least one bare portion of the distal end of the proximal rod against at least one bare portion of the proximal end of the distal rod, so that the sleeve keeps the proximal rod and the distal rod in electrical contact; and - inside the plug body, so as to space the proximal rod and the distal rod apart radially from the plug body. - a hollow plug body extending along a longitudinal axis and having a proximal end and a distal end along the longitudinal axis; - a heating rod: • having at least one distal portion extending axially and projecting from the distal end of the plug body; and • having a proximal end equipped with at least one connector for supplying the heating rod with electricity; • having at least one distal portion extending axially and projecting from the distal end of the plug body; and • having a proximal end equipped with at least one connector for supplying the heating rod with electricity; - at least one electrical connector, called the external connector, which: • projects axially from the proximal end of the plug body; and • is adapted to be capable of having a cable for supplying the glow plug with electricity connected to it; • projects axially from the proximal end of the plug body; and • is adapted to be capable of having a cable for supplying the glow plug with electricity connected to it; - a first, rigid, electrically conductive rod, called the distal rod, which is connected electrically, by a distal end, to at least one connector for supplying the heating rod with electricity; - a second, rigid, electrically conductive rod, called the proximal rod, which: • extends at least partially within the plug body; • is connected electrically, by a proximal end, to at least one external connector; and • is connected electrically, by a distal end, to a proximal end of the distal rod; characterised in that the glow plug also comprises an electrically insulating tubular sleeve which is mounted: • extends at least partially within the plug body; • is connected electrically, by a proximal end, to at least one external connector; and • is connected electrically, by a distal end, to a proximal end of the distal rod; - around the distal end of the proximal rod and the proximal end of the distal rod so as to clamp at least one bare portion of the distal end of the proximal rod against at least one bare portion of the proximal end of the distal rod, so that the sleeve keeps the proximal rod and the distal rod in electrical contact; and - inside the plug body, so as to space the proximal rod and the distal rod apart radially from the plug body.