Abstract: A fiber with which a further enhanced electric field intensity is obtained when a compressive force is applied across the longitudinal axis of the fiber. The fiber is composed of a potential generating filament having at least one interior angle of less than 120° in a contour shape in a sectional view in a direction perpendicular to a longitudinal axis of the fiber.

Abstract: A yarn that includes a fiber that generates a potential on a surface thereof by energy from the outside; and a grounded conductive core material covered with the fiber. The yarn generates a potential of 0.1 V or more on a surface thereof when measured under the following conditions: the yarn is stretched by a predetermined amount in a uniaxial direction; and the potential is measured with an electric force microscope.