PURPOSE: To precisely measure the natural property of soil on the spot by setting a cylindrical container containing a soil sample collected in natural state in a device at the sample-collected location and performing air and water permeability tests under a prescribed condition.

CONSTITUTION: A soil sample (a) is collected in a cylindrical container (b) in natural state by inserting the container (b) into a soil layer on the spot. Air compressed under a prescribed pressure is passed through the sample (a) layer by sucking 4 the air into a testing device in which the container (b) is set from a compressed air source B and the air permeability of the sample (a) is measured from the amount of air discharged 5 from the sample (a). Since the sample (a) is collected on the spot from the natural soil layer without collapse, the measured values are accurate values indicating the natural property of the soil on the spot. Then the water permeability of the sample (a) is measured similarly to the air permeability by passing pressurized water through the sample (a) layer in place of the compressed air by correspondingly applying the water permeability test data conventionally obtained in laboratories. This water permeability test is also precise, since the measurement is performed on the spot after the sample (a) is collected.