An earphone single-shaft structure includes a head strip, a cap body, and a single-shaft component. The single-shaft component is located at a housing of the cap body and connected to the head strip. The single-shaft component includes a body, a rotating shaft, a shaft hole, a pivot area and swinging areas. When the head strip rotates for a first angle about the pivot area, two ends of the head strip are located on one side of each swinging area, so that the cap body rotates in a first direction, and when the head strip rotates for a second angle about the pivot area, the two ends of the head strip are located on the other side of each swinging area, so that the cap body rotates in a second direction.