To provide a test boring device capable of simply achieving the work for positioning this device for the center of excavation on the ground surface and to provide a cylindrical member for positioning used in the test boring device.

The cylindrical member 81 for positioning is inserted in substantially vertical direction into a hole 79 for positioning dug in the ground E while its upper part protrudes from the ground E. A recessed fitting part for positioning the test boring device 1 in the horizontal direction on the ground E by pressing the test boring device against a side face part of the cylindrical member 81 for positioning in the horizontal direction while fitted into the side face part of the cylindrical member 81 is formed on a pedestal 3 of the test boring device 1 for drilling hole in the ground E.