This DNA complex 1 comprises a support 11 and a DNA 12 immobilized on the support 11. When the total DNA included in the DNA complex 1 is 100% by mass, at least 80% by mass of the DNA 12 is a single-chain DNA and the average molecular weight thereof is at most 500,000. The carrier 11 comprises an inorganic material. The average particle size of the DNA complex 1 is at least 10 μm.