Abstract: A method of coupling a container body (2) and a cover member (3) in a capsular container (1) includes a filling step for filling liquid medicine, powdered medicine, or granular medicine in the container body (2), and a fitting step for fitting the container body (2) to the cover member (3) under an atmosphere at a negative pressure which is lower than atmospheric pressure. Consequently, the pressure inside the joined container (1) does not exceed atmospheric pressure, the filling (37) which fills the inside of the container (1) can be prevented from leaking out between the container body (2) and the cover (3), and it is also possible to prevent bending of the container (1) which starts from the weak portion of the container (1).