The utility model discloses a diesel heater relates to motor vehicle firewood oil heating device technical field. Which comprises an outer shell, the shell is discoid, be equipped with the inner chamber on the shell, the electrode slice that dispels the heat is down fixed interior intracavity, dispel the heat down one end and the first electrode support connnection of electrode slice dispel the heat between electrode slice and the last heat dissipation electrode slice PTC heating plate is located under to dispel the heat the one end of electrode slice on, and is connected with temperature controller's a pin, temperature controller's another pin through the electrode connection piece and second electrode support connnection, first electrode post and second electrode post extend to outside the shell to it is fixed with the shell. The heater have rate of heating fast, small, be convenient for the installation characteristics.