Is the PAMELA anomaly caused by supernova explosions near the Earth?

We show that the anomaly of the positron fraction observed by the PAMELA experiment can be attributed to recent supernova explosion(s) in a dense gas cloud near the Earth. Protons are accelerated around the supernova remnant. Electrons and positrons are created through hadronic interactions inside the dense gas cloud. Their spectrum is harder than that of the background because the supernova remnant spends much time in a radiative phase. Our scenario predicts that the antiproton flux dominates that of the background for ≳100GeV. We compare the results with observations (Fermi, HESS, PPB-BETS, and ATIC).