To provide a medical tube for flow measurement, a medical container for flow measurement, and an apparatus for measuring drainage flow, for accurately measuring the flow of a liquid excreted from a patient.

As urine excreted from the patient K flows from a buffer tank 21 into a measurement tube 22, the interior of the measurement tube 22 is brought into a full-of-water state. Since the urine passes through the measurement tube 22 in this state, the flow of urine can be accurately measured by an electromagnetic flowmeter 30. Besides, since the state of electrical equilibrium is kept between the urine and detection electrodes 33 and 33, the flow measurement of urine can be accurately performed till a urine collection bag 10 is filled up irrespective of the state of urine excretion from the patient K.