A load testing device or the like having a structure in which cooling air does not leak, is provided. A load testing device includes: a resistance unit having a resistor and a resistor holding frame holding the resistor; a cooling unit having a cooling fan; and an insulating frame disposed between the resistance unit and the cooling unit. The insulating frame is coupled with the resistance unit. The insulating frame is coupled with the cooling unit. The insulating frame covers a side surface of a flow path of cooling air from the cooling unit to the resistance unit between the cooling unit and the resistance unit.