A light source apparatus for an endoscope, which has a lamp, a power source, a light adjustment control module that controls power to be supplied to the lamp within a range not more than an upper limit power based on a brightness instruction signal, and a continuous lighting sensing module that measures a continuous lighting time period from time when the lamp shifts from being extinguished to being lighted, compares the continuous lighting time period with a predetermined upper limit time period, and initializes the continuous lighting time period while the lamp is extinguished, wherein the upper limit power is set to a first upper limit power when the continuous lighting time period has not reached the upper limit time period, and changed to a second upper limit power lower than the first upper limit power in a stepwise manner when the upper limit time period has not been reached.
