A plunger includes a conductive base layer, and a platinum group layer which is provided on the outside of the base layer and which contains a platinum group element as a main component. The plunger has the base layer as its base material, and has the platinum group layer on the outside of the base layer at the tip part to come into contact with an inspection object. A contact probe includes the plunger, and a spring which abuts on the plunger at an end part.