This study tested the manner in which attitude toward an object of rumor affects people's epistemic motivation to solve a problem and to share a rumor, specifically on social media, using two rumors regarding food safety issues including McDonald's and genetically modified food. An online survey administered to 184 undergraduate students who use Twitter showed that negative attitudes increased the likelihood of rumor sharing, mediated by issue-related epistemic motivation. However, positive attitudes showed no effects on issue-related motivation and the likelihood of rumor sharing. Theoretical and practical implications are discussed.