A method is for preparing a medical/chemical solution by mixing a medical/chemical substance housed in a sealed container with a solution housed in a bag. The method includes transferring, from the bag into a syringe, an amount of the solution that is to be injected into a plurality of the containers. With the container and the syringe being held, at least one of a robot and a syringe driver configured to drive a plunger of the syringe is controlled so as to inject the amount of the solution into the plurality of the containers from the syringe.
