order the first comparison means comparator 52 compares the physiological data received by the data receiving means 51 with a predetermined threshold the user may arbitrarily set any threshold and vary the set threshold depending on the physiological condition measured by the measurement means 3 the threshold is adjusted so that physiological data exceeding the threshold should indicate an unusual state for example for a surgeon having a usual heart rate of 60 beats per minute the threshold may be set as 100 beats per minute in this case a heart rate more than 100 beats per minute is considered as an unusual state the threshold may be set as a value usual value u03b1 that is slightly higher than the usual value the usual value is previously calculated about the usual state of the surgeon in his daily life alternatively the threshold may be equivalent to the physiological data obtained when the surgeon is in an unusual state if the physiological data exceeds the threshold the first comparison means 52 allows for the first sampling means 53 described below to be activated on the other hand if the physiological data is below the threshold the first comparison means 52 compares the next physiological data with the threshold if the first comparison means 52 detects that the physiological data is.