An inherent information generating device adapted to an integrated circuit includes a plurality of pairs of source memory cells and a comparison circuit. One of the pairs of source memory cells includes a first source memory cell with a first electrical parameter value and a second source memory cell with a second electrical parameter value. The comparison circuit, coupled to the pairs of source memory cells and configured to generate inherent information of the integrated circuit, includes a first comparator. The first comparator is coupled to the first and second source memory cells, and is configured to compare the first electrical parameter value with the second electrical parameter value, and generate the bit value of a first bit of the inherent information according to the comparison result.