A neutron beam detection apparatus includes a scintillator configured to generate light when a radial ray is incident thereon, an optical fiber configured to cause light generated in the scintillator to be transmitted therethrough, and a discrimination section configured to receive light transmitted through the optical fiber and to discriminate a detection signal from a signal related to a neutron beam when a wave height of a detection signal related to the received light exceeds a determination threshold value Q th . The discrimination section adjusts the determination threshold value in accordance with deterioration of the optical fiber.
