A measurement device comprising: a housing for attaching a biosensor with a reagent selectively responding to a blood glucose in a biological fluid, the housing being configured to be carried by a user; a blood glucose measurement section within the housing configured to measure a concentration of the blood glucose, using the biosensor; a motion measurement section within the housing configured to measure a motion level of the housing based on vibration applied to the housing, wherein the motion measurement section determines an orientation of the housing with respect to a horizontal and, based upon the determined orientation, measures the vibration applied to the housing after a predetermined time period; a central processing unit within the housing configured to calculate a living activity level of the user in terms metabolic equivalents, based on the motion level of the housing measured by the motion measurement section, the living activity means an activity like sleeping or eating a meal, which cannot be designated as exercise (sports); a recording section within the housing configured to record the living activity level calculated by the central processing unit; characterized in that the CPU is programmed to detect two or more waves of the living activity levels recorded over the preceding 3 hours in the recording section greater than a first threshold of the MET type, to identify an interval between the two waves, to determine a meal event if the interval is longer than a first predetermined time and shorter than a second predetermined time and the living activity level between the two waves falls within a third threshold of MET type to a fourth threshold of MET type, to record the interval as meal time when the interval is longer than the first predetermined time and shorter than the second predetermined time and the living activity level between the two waves falls within the third threshold of MET type to the fourth threshold of MET type, to record the concentration of the blood glucose measured by the blood glucose measurement section as postprandial blood glucose level when the interval is recorded as meal time and to record the concentration of the blood glucose measured by the blood glucose measurement section as preprandial blood glucose level when a meal event is not determined by the CPU. a housing for attaching a biosensor with a reagent selectively responding to a blood glucose in a biological fluid, the housing being configured to be carried by a user; a blood glucose measurement section within the housing configured to measure a concentration of the blood glucose, using the biosensor; a motion measurement section within the housing configured to measure a motion level of the housing based on vibration applied to the housing, wherein the motion measurement section determines an orientation of the housing with respect to a horizontal and, based upon the determined orientation, measures the vibration applied to the housing after a predetermined time period; a central processing unit within the housing configured to calculate a living activity level of the user in terms metabolic equivalents, based on the motion level of the housing measured by the motion measurement section, the living activity means an activity like sleeping or eating a meal, which cannot be designated as exercise (sports); a recording section within the housing configured to record the living activity level calculated by the central processing unit; characterized in that the CPU is programmed to detect two or more waves of the living activity levels recorded over the preceding 3 hours in the recording section greater than a first threshold of the MET type, to identify an interval between the two waves, to determine a meal event if the interval is longer than a first predetermined time and shorter than a second predetermined time and the living activity level between the two waves falls within a third threshold of MET type to a fourth threshold of MET type, to record the interval as meal time when the interval is longer than the first predetermined time and shorter than the second predetermined time and the living activity level between the two waves falls within the third threshold of MET type to the fourth threshold of MET type, to record the concentration of the blood glucose measured by the blood glucose measurement section as postprandial blood glucose level when the interval is recorded as meal time and to record the concentration of the blood glucose measured by the blood glucose measurement section as preprandial blood glucose level when a meal event is not determined by the CPU.