A 45-year-old female who had cardiac surgery 40 years earlier was transferred to our hospital because of refractory fever. Echocardiography showed an intrapericardial mass. Gallium-67 (67Ga) scintigraphy revealed abnormal accumulation at the same site of the intrapericardial mass and thoracoscopy revealed that the mass was a pericardial abscess (PA). After surgical resection, drainage and antibiotic therapy, her fever subsided and the abnormal accumulation of 67Ga disappeared. This case showed a very rare clinical course of PA and the importance of 67Ga scintigraphy for its diagnosis.