Abstract: Method of manufacturing containers for dispensing solutions, includes the steps of: (a) extruding a parison from a die while injecting supporting air into the parison, and sealing a forward part of the extruded parison; (b) forming a middle portion of the parison constituting a barrel portion of a container to be produced, during extrusion of the parison, so as to have a wall thickness thinner than the forward part of the parison; (c) injecting air into the parison, after being inserted into a mold with a vacuum mechanism, to blow it out while keeping a pressure in the interior of the mold to a value lower than an internal pressure of the parison, and cutting off the parison from the die to form a container, (d) inserting a mandrel into the molded container through a cut opening of the container after transferring the mold retaining the molded container to a solution-charging station and charging a medical solution into the molded container; and (e) pulling the mandrel out of the container after charging a me