An image pick-up apparatus includes an image pick-up device which picks-up an image of a subject and outputs an image signal, a first-amplitude changing portion which varies an amplitude of the image signal outputted form the image pick-up device, a second-amplitude changing portion which varies the amplitude of the image signal to be outputted, a comparing portion which compares the amplitude of the image signal with a value of a target amplitude, and a control portion which controls the first- and second-amplitude changing portions based on the comparison result of the comparing portion and changes the amplitude of the image signal so that it is approximate to the target amplitude so that an observed image of the subject displayed on display means has a desired brightness.