To provide a DNA base sequence that gives a DNA/heme complex having a high peroxidase activity.SOLUTION: No method has been proposed so far which obtains a DNA sequence having a high peroxidase activity, except a DNA with a random variation incorporated thereinto. The inventors of the present invention have attempted to repeatedly design a sequence of a DNA aptamer having a G-quartet structure and measure the activity thereof multiple times by using an intra-computer evolutionary imitation algorithm, and have successfully designed a DNA aptamer having a G-quartet structure that brings a higher peroxidase activity than previously reported. For this reason, the present invention relates to a DNA that provides a DNA/heme complex with a novel base sequence having a high peroxidase activity.SELECTED DRAWING: Figure 1