In a medical device, a field-of-view switching mechanism which moves a field of view imaged by an observation section, and an illumination-light switching mechanism including an illumination section having an illumination range of illumination light whose entire field of view is covered by movement, are configured integrally with each other. The illumination light is illuminated to the current field of view by moving the illumination range of the illumination light, in synchronism with pivoting of an observation and in compliance with the field of view.