A sleeve soldering device has a displacement sensor and a heat flux sensor. The displacement sensor detects a physical quantity related to a pressure from a heated sleeve heated by a heater onto an electric board when the heated sleeve presses the electric board. The displacement sensor detects a physical quantity related to a deformation amount of the electric board due to thermal energy from the heater. The heat flux sensor detects a physical quantity related to a heat transfer amount from the heater to the electric board when the heated sleeve is pressed to the electric board. A control part compares each of detection values obtained from the displacement sensor and the heat flux sensor with a respective judgment reference so as to detect whether each detection value satisfies the respective reference.