To accurately grasp an average substance migration characteristic of a sample by a quantitative data.

This testing device is provided with the first chamber constitutive member 3 for constituting the first chamber 3a along the first plane (the first face) W1 of the sample W, and the second chamber constitutive member 4 for constituting the second chamber 4a along the second plane (the second face) W2 of the sample W, the first chamber constitutive member 3 is provided with the first flow-in port 32a and the first flow-out port 32b, the second chamber constitutive member 4 is provided with the second flow-in port 42a and the second flow-out port 42b, the first sensor 34 is provided in a first flow-out port 32b side to detect tracer water B after passed through the first chamber 3a, and the second sensor 44 is provided in a second flow-out port 42b side to detect the tracer water (tracer fluid) B which has flowed out into the second chamber 4a, and conveyed by the second flashing water (second flashing fluid) D passed through the second chamber 4a.