A 26-year-old man, who had received a ventriculo-peritoneal shunt for obstructive hydrocephalus after possible encephalitis, complained of disturbance of upward gaze and difficulty in movement seven months after the shunt implantation. One month later, neurological examination revealed upward gaze paresis and rigidity of all four limbs, but the neuroimaging studies revealed no ventricular dilatation. His symptoms deteriorated, and tremor of the extremities appeared. He was admitted to our hospital 10 months after the shunt implantation. He developed akinetic mutism soon after admission. Cerebrospinal fluid protein was elevated (62 mg/dl). At that time, the shunt reservoir was found to be insufficiently filled, and neuroimaging showed dilatation of the lateral and third ventricles with no dilatation of the fourth ventricle. A neuroendoscopic third ventriculostomy with removal of the previous shunt system gradually resolved the parkinsonism within two months, and the patient became capable of walking. The dilatation of the ventricles improved on neuroimaging. The present report suggests that shunt malfunction should be suspected when parkinsonism occurs in patients who have undergone a shunt placement, even though hydrocephalus on neuroimaging is not observed.