The cochlear blood flow of healthy adult guinea pigs was measured with a laser Doppler flowmeter and flow dynamics were analyzed on the basis of autoregulation. Angiotensin II infusion was used to raise blood pressure, while phlebotomy was done to lower blood pressure. The characteristics of autoregulation of cerebral blood flow and muscular blood flow were also investigated. Cochlear blood flow was considered to have some autoregulation but was less than brain blood flow, which showed significant regulation. Muscular blood flow seemed to have no similar regulatory mechanism.