Internal carotid artery occlusion rarely recanalizes spontaneously. Awareness of signs of recanalization is important, as it may necessitate changing the treatment strategy. We report a case of new cortical infarction outside the border zone, which led to the realization of internal carotid artery recanalization and revascularization. A 76-year-old woman presented with mild dysarthria. Magnetic resonance imaging showed cerebral infarction in the left-hemispheric border zone and occlusion of the internal carotid artery origin. Cerebral angiography performed showed complete occlusion of the internal carotid artery origin and intracranial collateral blood flow from the external carotid artery through the ophthalmic artery. She was diagnosed with infarction due to a hemodynamic mechanism caused by internal carotid artery occlusion and was treated with supplemental fluids and antithrombotic drugs. Four days after hospitalization, the right paralysis worsened and a new cerebral infarction was observed in the cortex, outside the border zone. This infarction appeared to be embolic rather than hemodynamic; thus, we suspected recanalization of the internal carotid artery. The patient underwent emergency cerebral angiography again, which revealed slight recanalization. Thus, emergency revascularization and carotid artery stenting were performed. New cortical infarcts outside the border zone in patients with complete internal carotid artery occlusion is an important finding, suggesting spontaneous recanalization of the occluded internal carotid artery.