A 6-year-old girl presented to hospital with a 4 day history of increasing neck pain. White blood cell count was normal with slightly raised C-reactive protein. The patient had a limited range of neck movement, and experienced enhanced pain with neck extension. X-ray and cervical computed tomography (CT) confirmed the diagnosis of cervical intervertebral disc calcification (IDC) and IDC with ossification of the posterior longitudinal ligament (OPLL), respectively. The symptoms improved after approximately 1 week following rest and oral acetaminophen. X-ray 6 months after onset confirmed the disappearance of the calcification. IDC is often reported in children, but IDC with OPLL is extremely rare and has not been previously reported in Japan. We believe that IDC with or without OPLL in children has a good prognosis when treated conservatively.