PURPOSE: To provide a vessel for infusion liquid which does not require much labor or complicated maneuvering, is free from risk of leakage of the mixed medicine, uses a lesser number of component parts, and can mix the medicine with a solvent liquid aseptically.

CONSTITUTION: A vessel for infusion liquid is composed of a medicine vessel 1, solvent vessel 2, two-headed needle 3, guide barrel 4, cap 5, and vial guide 6, wherein the guide barrel 4 is connected at its connection part 42 with the communication part, and also the open end of the barrel is sealed with a cap 5, and the two-headed needle 3 is accommodated in the guide barrel 4 with slidability downward. In the cap 5, the vial guide 6 is accommodated, and therein the medicine vessel 1 is accommodated and borne. When the cap 5 is rotated clockwise, the vessel 1 sinks together with the vial guide 6, and the needle 3 pierces a rubber plug 12 of vessel 1 and a closing membrane 22 of solvent vessel 2, and thus the two vessels 1, 2 are put in communication.