1. A medical apparatus system comprising: a medical apparatus including an observing section having an objective lens; an image generating section on an inside of an observation field of view that generates an image in the observation field of view obtained from the observing section; an information collecting section that collects information including at least a position on a distal end side of a treatment instrument that can be used together with the medical apparatus; a distortion setting section that sets virtual distortion on an outside of the observation field of view from a characteristic of distortion of the objective lens; a distorted image generating section on the outside of the observation field of view that generates at least a three-dimensional or two-dimensional distorted image virtually distorted on the outside of the observation field of view with respect to the treatment instrument on the basis of the information collected by the information collecting section and the virtual distortion; and an image combining section that generates, when the treatment instrument is captured on the inside of the observation field of view, a combined image such that an image of the treatment instrument on the inside of the observation field of view and a distorted image of the treatment instrument on the outside of the observation field of view coincide with each other in a boundary of the observation field of view.