A 62-year-old man with local recurrence of pancreatic cancer underwent his 17th infusion of contrast medium. He had no history of allergy and had not experienced any side effects from the contrast medium during any of the previous examinations. During infusion, he complained of nausea, followed by a loss of consciousness. He was injected intramuscularly with 0.3 mg adrenalin; however, he temporally went into cardiopulmonary arrest. He was therefore injected with 100 mg hydrocortisone and the continuous infusion of dopamine for shock. His electrocardiogram revealed ST elevation. An urgent cardiac echo evaluation revealed hyperkinetic wall motion. As his blood pressure increased after the initiation of the treatment, the ST elevation started to normalize. After transportation to an intensive care unit, the patient did not show chest pain, ST elevation on cardiograms, or any increase in the levels of cardiac markers. Based on his clinical course, the cause of the patient's ST elevation was considered to be coronary vasospasm. Kounis syndrome is the concurrence of acute coronary syndromes with conditions associated with mast cell activation, including allergic or hypersensitivity and anaphylactic or anaphylactoid insults. In cases of coronary vasospasm with shock due to contrast medium, supportive therapy using catecholamine, which has coronary vasodilator activity, and a steroid might be effective to treat the coronary vasospasm. Attention should therefore be paid to the patient's complaints, the findings of real-time cardiosonography, electrocardiograms, and the levels of cardiac markers to ensure a correct diagnosis and to achieve a good treatment outcome.