An imaging apparatus for endoscopes includes an endoscope relaying an object image through an observing optical system, and an imaging section removably mounted to the rearmost end of the endoscope, including a stop unit provided with a variable stop capable of changing an aperture size thereof, an imaging lens system, a focus lens system, and an image sensor. The relative positions of the variable stop, the imaging lens system, and the image sensor are constant, and the focus lens system can be moved along the optical axis of the imaging section. In this way, the imaging apparatus for endoscopes can be provided which is simple in structure, small in size, and low in cost.