The ΔΔ dibaryon resonance d⁎(2380) with (JP,I)=(3+,0) is studied theoretically on the basis of the 3-flavor lattice QCD simulation with heavy pion masses (mπ=679,841 and 1018 MeV). By using the HAL QCD method, the central Δ-Δ potential in the S37 channel is obtained from the lattice data with the lattice spacing a≃0.121 fm and the lattice size L≃3.87 fm. The resultant potential shows a strong short-range attraction, so that a quasi-bound state corresponding to d⁎(2380) is formed with the binding energy 25-40 MeV below the ΔΔ threshold for the heavy pion masses. The tensor part of the transition potential from ΔΔ to NN is also extracted to investigate the coupling strength between the S-wave ΔΔ system with JP=3+ and the D-wave NN system. Although the transition potential is strong at short distances, the decay width of d⁎(2380) to NN in the D-wave is kinematically suppressed, which justifies our single-channel analysis at the range of the pion mass explored in this study.