Disclosed is an apparatus and method of acquiring images created by penetration of a radioactive ray. The apparatus includes a scintillator to generate a light signal in response to an irradiated radioactive ray, and to change an advancing direction of the generate light signal, a light receiving unit to receive the light signal whose advancing direction is changed, and a signal processing unit to convert the received light signal into an electrical signal, and acquire an image corresponding to the penetrated irradiated radioactive ray based on the converted electrical signal.