The present invention addresses the problem of providing a flame treatment device which is capable of performing a flame treatment on a metal-based base material without requiring a preheat treatment. For the purpose of solving the above-described problem, a flame treatment device according to the present invention comprises: a first temperature measurement unit which measures the temperature of a metal-based base material before a flame treatment; a control unit which determines the combustion energy of flame on the basis of the temperature before a flame treatment, said temperature having been measured by the first temperature measurement unit, so that the surface temperature of the metal-based base material during the flame treatment is 56° C. or higher; and a flame treatment unit which performs a flame treatment on the metal-based base material on the basis of the combustion energy, which has been determined by the control unit.