A thermal analysis apparatus includes: a cylindrical heating furnace extending in an axial direction; a weight detector arranged on a rear-end side in the axial direction of the cylindrical heating furnace and including levers extending in the axial direction to detect a weight; a connecting portion for connecting the cylindrical heating furnace and the weight detector to communicate an internal space of the cylindrical heating furnace with an internal space of the weight detector and positioning the levers from the weight detector into the cylindrical heating furnace; sample holding portions connected to tip ends of the levers and arranged inside the cylindrical heating furnace and holding a sample; resistance heaters arranged to cover the weight detector and energized by an electric current of 6 A or less; and a heater control part for controlling an energization state of the resistance heaters to maintain the weight detector at a constant temperature.