Abstract: A vacuum furnace for brazing aluminum with brazing metal containing magnesium in which evaporated magnesium in the furnace is oxidized before aluminum members having been brazed are taken out, and/or the temperatures of a movable wall serving to control the communication between a vacuum pump and a heating chamber during heating and of an inner surface of the heating chamber are maintained at above a specified temperature at which evaporated magnesium does not adhere, and/or a heating member which is to be excited electrically and electrodes used for electrically exciting the heating member, which are the constituents of a heater for heating the aluminum members and the brazing metal, are hermetically sealed and insulated from the inside of the heating chamber.