A blood pressure monitor manufacturers for monitoring a blood pressure of a living subject, comprising: a first-change-value calculating device for calculating a first change value as a change of each of a plurality of blood pressure values iteratively obtained from the subject, from a standard blood pressure obtained from the subject; a relationship obtaining device for obtaining a relationship between first reference range and standard blood pressure monitor manufacturers wherein a plurality of different first reference ranges correspond to a plurality of different standard blood pressures, respectively; a first-reference-range determining device for determining a first reference range based on the standard blood pressure obtained from the subject and according to the relationship between first reference range and standard blood pressure obtained by the relationship obtaining device; and an abnormality judging device for judging that the blood pressure of the subject is abnormal when the first change value calculated by the first-change-value calculating device does not fall in the first reference range determined by the first-reference-range determining device.
A blood pressure monitor manufacturers apparatus according to claim 6, further comprising: a third-reference-range determining device for determining a third reference range; wherein the abnormality judging device judges that the blood pressure of the subject is abnormal when said each of said blood pressure values does not fall in the third reference range determined by the third-reference-range determining device.