A 52-year-old woman was admitted to our hospital because of colonic diverticulitis. Ceftriaxone (CTRX) was administered at the dose of 2 g/day for 8 days. The patient complained of right hypochondralgia 15 days after the start of CTRX administration. Abdominal computed tomography and ultrasonography revealed stones and sludge in the gallbladder and common bile duct, and thickening of the gallbladder wall. In addition, drip-infusion cholangiographic computed tomography demonstrated acute curvature of the gallbladder neck, which lay close to the bile duct. We diagnosed acute cholecystitis caused by CTRX- associated biliary pseudolithiasis. Emergency laparoscopic cholecystectomy was performed, considering the risk of bile duct injury if the inflammation worsened. Laparoscopy revealed a right-sided ligamentum teres. We started dissection from the gallbladder fundus, and resected the gallbladder without causing bile duct injury. The common bile duct stone disappeared on postoperative day 3, and the patient had a satisfactory postoperative course.