In an interference evaluation device, an axis value obtaining unit obtains posture information indicating a posture to be taken by a welding robot, on the basis of teaching information for teaching an operation to the welding robot. A reference point calculation unit, an extension direction calculation unit, and an evaluation value setting unit generate evaluation information indicating a degree of bend of a torch cable, which is caused by the torch cable contacting an arm of the welding robot, by using the posture information obtained by the axis value obtaining unit. The torch cable is included in a welding tool attached to an end of the arm and extending in a direction away from a welding torch of the welding tool. An evaluation value output unit outputs the evaluation information generated by the reference point calculation unit, the extension direction calculation unit, and the evaluation value setting unit.