An output setting device of a constant current circuit comprises a reference current generating circuit (11) and first through fourth current mirror circuit groups (21-24). The reference current generating circuit channels a reference current (Iref). The current mirror circuit groups have at least one current mirror circuit channeling a current proportional to the reference current. One current mirror circuit group among the plurality of current mirror circuit groups, or two or more current mirror circuit groups connected to each other in parallel, are connected to a load, and the current supplied to the load is set.