To provide a measurement method and a measurement device, capable of measuring a substance which is unstable in air, using a simple procedure and collecting a sample by using a sensor separated from the measurement device.

This measurement device is provided with a first electrode 1 having an insulating member with a recess part for holding a sample and a microelectrode arranged inside the recess part, a second electrode 3 paired with the first electrode via a substance transmitting medium M, an electric controller 23 giving an electric state change between the microelectrode and the second electrode, and a detecting means 23 for detecting an oxidation- reduction reaction occurring between the micro electrode and the second electrode as an electric signal. Using this measurement device, a measurement object included in the sample and related to the oxidation-reduction action or the electric signal detection is measured.