Kurt Busch -- No Criminal Charges ... In Domestic Violence Case (Update)

10:47 AM PT -- Busch's ex-GF also issued a statement saying she's "disappointed that full justice was not served here."

10:30 AM PT -- Busch just issued a statement saying, "I am grateful that the prosecutors in Delaware listened, carefully considered the evidence, and after a thorough investigation decided to not file criminal charges against me."

He continued, "As I have said from the beginning, I did not commit domestic abuse. I look forward to being back in racing as soon as possible and moving on with my life."

Prosecutors have decided they will NOT pursue criminal charges against NASCAR driver Kurt Busch over an alleged domestic violence incident ... claiming there's just not enough proof.

Busch was accused of slamming his ex-GF's head against the wall of his trailer during an altercation in Dover, Delaware back in September.

But a rep for the Delaware Attorney General's Office says ... after a thorough investigation, "the admissible evidence and available witnesses would likely be insufficient to meet the burden of establishing beyond a reasonable doubt that Mr. Busch committed a crime."