A heat-melting glue gun including a body shell in which a heating member containing a heat-melting glue stick, a glue stick feeding means, a gas cylinder, and a current producer are mounted. A conduit pipe extends from the gas cylinder to end with a nozzle located below the heating member which is wrapped with a layer of thermal conductive net with good heat transfer ability. Wire lines having first ends connected to positive and negative electrodes of the current producer extend their second ends to points properly above the nozzle. When a flint in the current producer is struck, an instantaneous current is generated to cause a short-circuit spark to occur between the two second ends of the wire lines. Gas supplied from the gas cylinder and jetting from the nozzle is ignited by the spark to burn below the heating member, causing the glue stick in the heating member to be heat melted.