An in vivo examination apparatus including an objective unit capable of being readily replaced during examination is provided. The in vivo examination apparatus includes a main body, a vibration suppressor configured to suppress vibrations in an examination region of an object under examination, and an objective optical system configured to observe the examination region where the vibrations are suppressed. The objective optical system and the vibration suppressor are attached to the main body. The objective optical system is attachable to and detachable from the main body in a direction crossing an optical-axis direction of the objective optical system.