Illumination apparatus for adjusting color temperature and brightness and illumination system including the same

Disclosed are an illumination apparatus for adjusting a color temperature and brightness, which can determine duties of pulse width modulation (PWM) control pulses for driving two light sources having different color temperatures, and an illumination system including the same. The illumination apparatus includes first and second light source units emitting light of different color temperatures, first and second pulse width modulation (PWM) driving units respectively driving the first and second light source units by a PWM control method, and a duty control unit controlling respective duties of PWM control pulses of the first and second PWM driving units according to a color-temperature set value and a brightness set value input from the outside. The duty control unit controls the duties such that the color-temperature set value is reflected in the respective duties of the PWM control pulses of the first and second PWM driving units in a complementary relation.