Is it free to reject the application for invention patent?

It's free. The rejection of an application for a patent for invention refers to China National Intellectual Property Administration's decision not to grant a patent right because he thinks that there are still substantial defects in the application for a patent for invention after the applicant's defense, so the rejection of an application for a patent for invention is free.

Legal basis:

People's Republic of China (PRC) Vocational Law

Article 37 If the administrative department for patent in the State Council considers that the application for a patent for invention is not in conformity with the provisions of this Law after substantive examination, it shall notify the applicant and ask him to state his opinions within a specified time limit. If he fails to reply within the time limit, his application shall be deemed to have been withdrawn.

Article 38 If an application for a patent for invention is still not in conformity with the provisions of this Law after the applicant has stated his opinions or made amendments, it shall be rejected.