To provide a biological information detector, etc., wherein the detection of biological information in the same object region is easily and inexpensively attained with excellent reproductivity.

The biological information detector 10 includes a biological information detecting means 20 and a resistance measuring means 30. The biological information detecting means 20 detects the biological information inside a living body from the external part of the living body. The resistance measuring means 30 is a means for measuring the electric resistance of the living body, and used for detecting an electric unique part. The electric unique part is the part which has the extremal value of the electric resistance in the living body and provides a reference position when specifying the position of the part to be detected by the biological information detecting means 20.