A soldering apparatus which can keep an interior of a chamber at a specified vacuum pressure and can perform soldering in the chamber, the vacuum pressure of which is optimally adjusted, is provided with a chamber (40) in which a work (1) is solderable under vacuum environment, an operation part (21) that inputs and sets vacuum pressure in the chamber (40), a pump (23) that performs vacuum drawing on the interior of the chamber (40), a pressure sensor (24) that detects pressure in the chamber (40), and a control portion (61) that adjusts the set vacuum pressure in the chamber (40) based on a pressure detection signal (S24) output from the pressure sensor (24), and keeps the set vacuum pressure for a predetermined period of time, as shown in FIG. 4.