Abstract: An evaluating device for evaluating a joining operation of joining a first base material with a second base material includes: a camera that capture images of the joining operation; a processor that acquires, from the images, time-series data of one or more of a position of the first base material, a position of the second base material, a position of a flame, a position of a brazing filler metal, a temperature of the first base material during the joining operation, and a temperature of the second base material during the joining operation, and evaluates data before a wire feeding start timing and data after the wire feeding start timing among the time-series data; and a display that outputs results of evaluation.