PURPOSE: To provide an instrument for measuring bioinformations of a living body featuring easy operability and reliable storage protection of the measured data.

CONSTITUTION: This instrument comprises a main measurement unit 2, a memory unit 3 incorporating a battery 3a and a memory 3b and detachable from the main measurement unit, and a charge-transfer unit 5 capable of not only recharging the battery 3a but also transferring measured data stored in the memory 3b to an external storage unit 4. When recharging the battery 3a of the memory unit 3, a simple operation of detaching the memory unit 3 from the main measurement unit 2 and fitting the former onto the charge-transfer unit 5 can achieve both the recharging of the battery 3a and the transfer of the measured data stored in the memory 3b to the external storage unit 4. Its capability of charging the battery as well as transferring the measured data through a single operation of detaching and reconnecting can reduce the workload of an operator while ensuring the protection of the measured data stored in the external storage unit 4 with no risk of the data erasing.