A case of acute heart failure due to Takotsubo cardiomyopathy induced by 5-fluorouracil is described. Acute heart failure developed during the administration of 5-fluorouracil (5-FU) and levofolinate calcium in a 62-year-old woman who had underwent a Miles operation for rectal adenocarcinoma. Electrocardiography upon admission showed slight ST elevation in leads V1-3, and follow-up electrocardiography on the third hospital day evealed QT interval prolongation and giant negative T waves in leads II, III, aVF, and V1-6. Echocardiography and myocardial scintigraphy showed left ventricular apical ballooning in the acute phase of heart failure, but left ventricular contraction was normal during the recovery phase. Coronary angiography demonstrated normal coronary arteries, and multi-vessel coronary artery vasospasms including microcirculation disorders could be provoked by intracoronary acetylcholine infusion during, but not before, the intravenous administration of levofolinate calcium and 5-FU. The cause of heart failure in this patient, Takotsubo cardiomyopathy induced by multivessel coronary vasospasm including microcirculation disorders only during 5-FU administration, is notable.