The invention discloses a direct resistance type electric heater. The direct resistance type electric heater comprises a tubular housing, multiple heating elements are arranged in the tubular housing, the tubular housing is internally provided with multiple insulation support assemblies arranged at intervals, the heating elements are supported and fixed in an insulated mode through the insulation support assemblies, the lead-out ends of the heating elements are connected with conductive bars, metal protective tubes are welded on the tubular housing, the conductive bars pass through the metal protective tubes to extend out of the tubular housing, the upper ends of the metal protective tubes are provided with junction boxes, and the conductive bars extend into the junction boxes to form wiring ends. By using such a structure, the structural design is compact, the occupied space is small, heat is concentrated, the heating efficiency is greatly improved, besides, through arrangement of the conductive bars and sealing structures between the conductive bars and a metal protective housing, the safety and the reliability are ensured, the concrete structure of the insulation support assemblies, in particular, enables fluid pass performance to be quite good, and the heating efficiency is further improved.