Surface processing method of disk member of sealing apparatus, and sealing apparatus

A sealing apparatus for realizing sealing of an annular gap between a shaft and a hole into which the shaft is to be inserted, the sealing apparatus comprising:

• a sealing apparatus body fitted into the hole;
• and
• a slinger attached to the shaft,
• wherein the sealing apparatus body includes a reinforcing ring which is annular around an axis line, and an elastic body portion which is formed with an elastic body attached to the reinforcing ring and which is annular around the axis line,
• the slinger includes a flange portion which is a portion extending toward an outer periphery side and which is annular around the axis line,
• the elastic body portion includes an end-face lip which is a lip extending toward one side in an axis line direction, contacting the other side surface of the flange portion in the axis line direction, and annular around the axis line, and
• a plurality of fine spiral grooves are randomly formed on the other side surface of the flange portion of the slinger, wherein
• the grooves include grooves which have positions being displaced in a radial direction in each lap, grooves which break halfway, and grooves whose spiral shapes are not the same.