The purpose of the present invention is, when treating circulatory disease such as acute myocardial infarction, to correct a reduction in myocardial contractility and thereby prevent arrhythmia and the like, as well as to reduce infarct size. Provided is a neurostimulation device having a stimulus application part configured so as to apply a stimulus to a cervical or thoracic vagus nerve portion in a human or an animal, and a stimulus regulation part configured so as to regulate the quantity of stimulus applied from the stimulus application part to the vagus nerve portion. The stimulus regulation part establishes a quantity of stimulus that is less than a value at which adverse effects would be produced, determines the heart rate and R wave interval of the human or animal, and controls the quantity of stimulus on the basis of these determinations.
