An illumination apparatus includes: a series circuit of a thyristor and at least one load circuit connected across an AC power source; a current control circuit for adjusting an input current to be maintained at a predetermined level during a part or the whole of an ON period of the thyristor; and a short circuit for short-circuiting input ports of the load circuit to have a predetermined resistance during a part of the ON period of the thyristor and a part or the whole of an OFF period of the thyristor. The current control circuit and the short circuit are connected in parallel to the load circuit.