A structure includes a wristwatch case; an inner frame arranged inside the wristwatch case and having an upper surface provided with a positioning fitting recess; a timepiece module arranged as being positioned inside the inner frame; and a parting plate which is provided with a positioning pin that is provided on a lower surface of the parting plate facing the upper surface of the inner frame, and that is fitted into the positioning fitting recess of the inner frame, thereby positioning the parting plate with respect to respect to the inner frame. As a result, in a state where the timepiece module is arranged and positioned inside the inner frame arranged in the wristwatch case, the positioning pin of the parting plate can be fitted into the positioning fitting recess of the inner frame. Accordingly, the parting plate can be accurately positioned with respect to the inner frame.