Heparin-induced thrombocytopenia (HIT) type II is characterized by a decrease in platelet count and thrombosis following heparin administration. We anesthetized a 67-year-old woman with suspected HIT type II undergoing carotid endarterectomy (CEA). Preoperatively, the patient had received anticoagulation therapy with heparin for cerebral infarction due to thrombosis and she developed thrombocytopenia with deterioration of cerebral infarction. Platelet level recovered by discontinuation of heparin and platelet infusion. During the surgical procedure, a substitution for heparin as an anticoagulant was necessary and we used argatroban, a direct thrombin inhibitor, with monitoring activated coagulation time (ACT). The ACT values were maintained above 200 sec during endoarterectomy and the operation was successfully carried out. We believe that argatroban is one of the choices for anticoagulants in a patient with HIT type II.