A method for controlling an error rate of device-specific information, the method comprising: a first step (S1, S2) of: inputting each of i, i is an arbitrary natural number, pieces of input data, j times, j is an arbitrary natural number, into a physically unclonable circuit; processing j responses into j' pieces, j' is an arbitrary natural number, and 0 < j' ≤, and storing them in a storage means beforehand in association with each piece of the input data; a second step of: inputting the i pieces of the input data into the storage means; reading the j' responses corresponding to the respective i pieces of the input data from the storage means to concatenate the obtained j' responses for each piece of the input data; further concatenating the concatenated data by k' repetitions, k' is an arbitrary natural number and 0 < k' ≤ k, where k is an arbitrary natural number, and k is 2 or more when the i and the j are both; and further concatenating the obtained data for i pieces for different input data to generate reference data; a third step of: inputting the i pieces of the input data, k times, for each piece of the input data into the physically unclonable circuit; processing the obtained k responses into k' pieces to concatenate each of the obtained k' pieces of the responses by j' repetitions; further concatenating the j' responses for all of the k' pieces to obtain j' × k responses for each piece of the input data; and further concatenating the j' × k responses for each piece of the input data also for different input data; and generating synthesized output data including i × j' × k' responses; a fourth step of deciding whether or not the synthesized output data is in a same range as the reference data; and a fifth step of determining whether or not an error rate of the synthesized output data is within a preset range as a result of the decision in the fourth step, wherein if the error rate is determined not to be within the preset range in the fifth step, at least one of the i, j, j', k, and k' is changed to repeat the first through fifth steps until the error rate falls within the preset range, and wherein if the j' is a natural number of 2 or more in the first step, the j' responses are compressed into information indicating parts different from each other to be stored in the storage means. a first step (S1, S2) of: inputting each of i, i is an arbitrary natural number, pieces of input data, j times, j is an arbitrary natural number, into a physically unclonable circuit; processing j responses into j' pieces, j' is an arbitrary natural number, and 0 < j' ≤, and storing them in a storage means beforehand in association with each piece of the input data; a second step of: inputting the i pieces of the input data into the storage means; reading the j' responses corresponding to the respective i pieces of the input data from the storage means to concatenate the obtained j' responses for each piece of the input data; further concatenating the concatenated data by k' repetitions, k' is an arbitrary natural number and 0 < k' ≤ k, where k is an arbitrary natural number, and k is 2 or more when the i and the j are both; and further concatenating the obtained data for i pieces for different input data to generate reference data; a third step of: inputting the i pieces of the input data, k times, for each piece of the input data into the physically unclonable circuit; processing the obtained k responses into k' pieces to concatenate each of the obtained k' pieces of the responses by j' repetitions; further concatenating the j' responses for all of the k' pieces to obtain j' × k responses for each piece of the input data; and further concatenating the j' × k responses for each piece of the input data also for different input data; and generating synthesized output data including i × j' × k' responses; a fourth step of deciding whether or not the synthesized output data is in a same range as the reference data; and a fifth step of determining whether or not an error rate of the synthesized output data is within a preset range as a result of the decision in the fourth step, wherein if the error rate is determined not to be within the preset range in the fifth step, at least one of the i, j, j', k, and k' is changed to repeat the first through fifth steps until the error rate falls within the preset range, and wherein if the j' is a natural number of 2 or more in the first step, the j' responses are compressed into information indicating parts different from each other to be stored in the storage means.