A substrate treating device comprising a treatment chamber for storing and treating substrates and a heating device having a heating element and a heat insulator and heating the substrates in the treatment chamber by the heating element. The heating element is so formed that only its one end is held by a holding part, and a projection projected to the treatment chamber side at the intermediate part of the heating element and positioned in proximity to or in contact with the heating element is formed on the heat insulator. A pin with an enlarged part is passed through the heating element and the heat insulator at the intermediate part of the heating element and the enlarged part is positioned in proximity to or in contact with the heating element. The plurality of projections may be formed on the heat insulator and the pins may be disposed between these plurality of projections.