An endoscope apparatus includes a light source apparatus, an image processing circuit configured to subject a first image or a second image obtained by irradiating first or second narrow band light to predetermined image processing and output the image, and a control circuit configured to perform control to acquire signal intensity information about a signal intensity of the image pickup signal outputted from the image pickup device in response to irradiation with the first narrow band light based on a current operation state of a light source configured to generate first narrow band light and further maintain a ratio of respective brightnesses of the first image and the second image used for generating the observation image to be a predetermined ratio based on the signal intensity information.
