Various psychiatric symptoms, including depressive mood, cognitive dysfunction, and psychosis, have been observed in the course of Wilson disease, however both domestic and international case reports on Wilson disease presenting with typical mania before the onset of neurological or hepatic symptoms are rare. Even though the delayed diagnosis of Wilson disease can lead to irreversible impairment, including liver cirrhosis, diagnosis of Wilson disease usually takes more than two years for patients showing psychiatric symptoms as their first manifestation. Without careful observation and adequate understanding of the disease, clinicians may overlook signs and symptoms suggesting Wilson disease in patients showing typical psychiatric symptoms such as mania. In order to promote clinician's vigilance in detecting symptoms and signs of Wilson disease in patients showing symptoms of bipolar disorder, we report on a rare case of a 31-year-old male Wilson disease patient who developed symptoms of typical bipolar disorder before the onset of neurological or hepatic symptoms.