PURPOSE: To provide a testee unit which processes and stores an information obtd. by detecting a bio-information independently from a monitor by providing a signal conversion means for converting the analog signal from a bio- information sensor to a digital signal, a memory means, a communication means and a control means for outputting the data on the fixed quantity value of the bio-information.

CONSTITUTION: The bio-information sensor 38 starts detecting the specific bio- information of a patient when the patient unit is put into an operation mode and is placed in contact with the patient. A transducer 40, then, outputs the analog signal indicating the detected bio-information. The analog signal is passed through a signal adjusting means 42, by which the signal is adjusted and the analog signal is thereafter converted to the digital signal by an A/D converter 44. This digital signal is inputted to the control means 46. The control means 46 determines the signal fixed value indicating the instantaneous level of the patient's bio-information based on the signal and stores the value into the RAM 48a. The stored data is transmitted to a main unit monitor by the communication means 34.