To provide a flexible single plastic container such as a bag, a pouch or a bottle for containing and delivering intramuscular injection such as diagnostic contrast agent, nutritious agent and drugs in order to administer the injection to patients who are required to be administered.

After first and second polymer material sheets are superimposed each other, they are integrally sealed at the peripheral part forming an inner tank 40, and a closing member 10 integrally formed with this container 10 is disposed, at least an oval reinforcing member 50 in the center thereof is disposed. Thus, a flexible container for containing and delivering medical drugs by which preventing the breakage of a wall in the container and the drops remaining tendency inside.