In the management of various diseases, the condition of a patient can be known only from the various inspective or retrospective diagnoses at the hospital, and the change in the condition of a patient in daily life cannot be known exactly. From this point of view a portable biological information recording and analyzing system, MICRO (Medical Information Collection RObot) is developed here, which can record and analyze many kinds of biological signals in the patient's daily life, not only at hospital but also at home. The MICRO is a kind of a pocket-sized battery driven micro-computer system, and by carrying this, many kinds of medical information about the condition of a patient in his daily life can be acquired. The size or function of this small system should be changed according to its surrounding enviroment, purpose of recording, the object of measurement or the patient's condition. In practice two types of MICRO have been developed. One is a kind of event counter and is equipped with four button switches to record the occurrence time of objective events, and a mercury switch to record the patient's body swaying. The output of the mercury switch is affected by the patient's motion and is thought to indicate well the condition of a disease. This type of MICRO is applied to record pain fluctuation in the daily life of the rheumatoid arthritis patients. As a result, the pain fluctuation in one day is proved to be rather coincident with the condition of the patient. The other type is a kind of data recorder with an instrumentation amplifier and A/D converter, and it can record many analog types of biological signals, like electrocardiograms or the eletromyograms. A long-term monitoring of the electromyograms of paralyzed patients is one clinical application of this type. The other clinical application is a measurement of the pressure distribution under the foot. A new method has been needed to measure in more natural states, like in the wearing of shoes or where the electric wave does not arrive if using a telemetry system. The results show that the MICRO can stably measure the pressure under the foot in such natural states.