An assembling method of a capsule medical apparatus is provided. The capsule medical apparatus includes a sealed capsule container having an image pick-up unit which picks up an image of a portion illuminated by an illuminating unit, and an objective optical system which is arranged in front of the image pick-up unit. The assembling method includes a positioning step of positioning so that a relative position of a reference position of a fixing frame in the objective optical system matches a reference position of an image area of the image pick-up unit, and a fixing step of, after the positioning step, contacting a reference down-surface of the fixing frame with the top surface of the image pick-up unit and fixing the image pick-up unit and the fixing frame.