FORMING METHOD OF INTERMEDIATE LAYER FORMED BETWEEN BASE MATERIAL AND DLC FILM, DLC FILM FORMING METHOD, AND INTERMEDIATE LAYER FORMED BETWEEN BASE MATERIAL AND DLC FILM

An intermediate layer forming method to form an intermediate layer formed between a base material and a DLC film using a PVD method includes: a Ti layer film-forming step of film-forming a Ti layer on a base material; and a TiC layer film-forming step of film-forming a TiC layer on the Ti layer, in which in the Ti layer film-forming step, an Ar gas is supplied into a chamber into which the base material is carried and a film-forming pressure is set to a pressure in a range of not less than 0.4 Pa and not more than 1 Pa to film-form the Ti layer, and in the TiC layer film-forming step, an Ar gas and a CH 4 gas are supplied into the chamber, a film-forming pressure is set to a pressure in a range of 0.2 Pa or more to less than 0.4 Pa, and a second bias voltage higher in bias voltage than a first bias voltage applied to the base material in the Ti layer film-forming step and higher in bias voltage than -100 V is applied to the base material to film-form the TiC layer.