A medical apparatus includes: a first vessel for supplying a first liquid; a second vessel for supplying a second liquid; a mixing vessel for mixing the first and second liquids; a connector including a first flow passage connected to the first vessel, a second flow passage connected to the second vessel, a third flow passage connected to the mixing vessel and joined to the first flow passage and the second flow passage, and a discharge port which communicates with the third flow passage; and a flow passage opening/closing device provided in the third flow passage at a joint part where the first flow passage and the second flow passage join the third flow passage or at a part on a discharge port side relative to the joint part and which is operative to open/close the third flow passage.