Illumination apparatus and lighting device used thereby

An illumination apparatus includes light sources differing from one another in terms of light-emission color and voltage drop when identical current flows therein, switches in one-to-one correspondence with the light sources, a DC power supply circuit, and a control circuit. The control circuit performs a first control of the switches through a time division control method such that an on-period of each switch is not overlapped with that of any other switch. The control circuit also performs a second control to individually control at least one of a target current magnitude, flowing through each switch in the switched-on state, and a target on-period length of each switch, and to adjust a ratio of the plurality of light sources in terms of a product of the target current magnitude and the target on-period length.