In the foreword of Buddha, Tezuka said he was was some kind of sceptical buddhist.
I think he was a very liberal person: according to Tezuka World, he made some works for Japan's Communist Party in the seventies (). However, he was mostly apolythic.
I think that in the European point of view, he would be a Socialist, and in the American point of view, he would be a left-wing Democrat.