PROBLEM TO BE SOLVED: To provide an illuminating device capable of controlling a light amount to a target light amount with a high degree of accuracy without losing the balance in an outgoing light amount ratio among a plurality of semiconductor light sources, and also to provide an endoscope apparatus equipped with the illuminating device.SOLUTION: An illuminating device includes: a plurality of semiconductor light sources each of which emits light with a spectrum different from one another target light amount setting means for setting a target light amount for a total outgoing light amount light amount ratio setting means for setting an outgoing light amount ratio among the plurality of semiconductor light sources amplitude value setting means for setting an amplitude value of driving signal for each of the semiconductor light sources on the basis of the set outgoing light amount ratio and driving signal generating means for generating each driving signal through the use of common pulse modulation control based on the target light amount, while keeping the driving signal at the set amplitude value. When the target light amount is set, a driving pulse signal corresponding to the target light amount is set in common among the semiconductor light sources. The driving pulse signal is so set at the amplitude values corresponding to the outgoing light amount ratio as to generate individual driving signals for driving the respective semiconductor light sources.
