Purpose: This study investigated the framing effects of fact-check mark on rumor believability, specifically when the fact-checking evaluations are inconclusive. Method: Using two rumors regarding COVID-19, an online experiment (Fact-checking mark: half-true vs. half-false vs. withheld) with 273 Korean adults was conducted. Result: The results showed that fact-checking mark framed as half-false reduced rumor believability, whereas that framed as half-true increased rumor believability. The rumor believability changes in the half-false condition was found to be greater than those in the withheld condition. Also, the exposure to inconclusive fact-checking marks increased the rumor believability of individuals who had lower levels of prior rumor beliefs and decreased the rumor believability of individuals who had higher levels of prior rumor beliefs. Conclusion: This study enhances our understanding of how fact-checking evaluations influence individuals’ rumor believability.