Acute suppurative thyroiditis is a rare disorder that is mostly found in the left lobe of the thyroid gland of children due to congenital patency of the pyriform sinus fistula. Here, we report a 61-year-old man with acute right-sided suppurative thyroiditis without pyriform sinus fistula. He also showed infectious hip arthritis, spondylitis and Roth's spots. He presented with heart failure and was diagnosed with infectious endocarditis by sequential transesophageal echocardiography. A replacement with a prosthetic valve was performed and cured him. It is important to recognize that infectious endocarditis can be a focus of acute suppurative thyroiditis.