Kevin Costner tried to get a lawsuit against him over an alleged unscripted rape scene tossed out of court … it wasn’t thrown out completely, but about a chunk is now gone.

According to new legal docs, obtained by TMZ, the judge in the case denied his motion to throw out all 10 of Devyn LaBella‘s claims … and instead tossed two.

One of those involved sexual harassment and the other involved an alleged violation of the Bane Act, which is intended to combat hate crimes.

Costner’s attorney, Marty Singer, tells TMZ … “We were pleased to learn that the Court granted our anti-SLAPP motion in part, dismissing two of the plaintiff’s claims (including one of her claims for sexual harassment).”

He continues … “While we were disappointed with the Court’s decision to allow her remaining causes of action to proceed, the evidence is clear that they have no legal or factual merit, and we plan to appeal the Court’s decision promptly. In spite of the plaintiff’s outlandish allegations, there was never any ‘simulated rape,’ ‘simulated sex’ or sexual harassment – and absolutely no retaliation. Rather, she is seeking millions of dollars for agreeing to participate in the rehearsal of a single, benign shot that even she admits was explained to her in advance. We will continue to fight for the truth and we are extremely confident we will prevail.”

As we’ve told you … LaBella sued back in May, claiming she was forced to participate in an unscripted and unscheduled rape scene on the set of the Western film series, “Horizon.”

Kevin’s insisted there was NO violent rape scene on his set … and he’s called the lawsuit a shake down.