We propose a scenario for coronal heating as a result of body Joule heating of a twisting magnetic tube of ≈10 km radius due to anomalous resistivity, whose effective collision frequency is 10-2 times the electron plasma frequency. The kilo-Gauss faculae of 0.2 arcsec diameter in the photosphere are expected to split further by “collisions” with the non-magnetic eddies of various size owing to the large Reynolds number. The smallest size of a kilo-Gauss fluxtube which can be twisted lies just between frozen and non-frozen states, and it is ≈1 km. When expanded into the corona as a ≈10 km tube, the twisting inevitably makes a charge separation. The latter in turn produces a large electric field parallel to the magnetic field, which makes runaway electrons, and an anomalous resistivity is expected from instability between the runaway and bulk electrons. The anomalous resistivity will stop the runaway electrons and the process will be repeated. From these, we can obtain the correct order of magnitude of the coronal heating rate ≈10-4erg cm-3s-1. Facular body Joule heating as a result of small sizes is also proposed.