A contactor composed of polycrystalline diamond including a plurality of diamond particles, wherein: the contactor is configured such that a rotational axis passes through the center thereof, the contactor comprising a first portion that includes an inner end part and has a given thickness in the radial direction, and a second portion that includes an outer end part and has a reduced thickness in the radial direction; the second portion has a first surface that is continuous with the upper surface of the first portion, a second surface that is continuous with the lower surface of the first portion, and a connecting surface that connects the first and second surfaces and includes the outer end part; the angle θ formed by a first line segment indicating the first surface in a cross-section taken along the rotational axis and a second line segment indicating the second surface in said cross-section is 100-150° inclusive; the length between a first boundary part that is the boundary between the first surface and the connecting surface and a second boundary part that is the boundary between the second surface and the connecting surface is 1-10 µm inclusive; the length from the rotational axis to the outer end part is 1-10 mm inclusive; and the average grain diameter of the plurality of diamond particles is 0.1-100 µm inclusive.