Disclosed herein are an apparatus and method for generating secret information. The apparatus includes a data communication unit for receiving a request to output a content value and outputting the content value; and a microcontroller unit for generating a Physically Unclonable Function (PUF) response based on the content value, calculating the characteristic value of the PUF response, and generating secret information using the PUF response, the error of which is corrected using the characteristic value.