[Abstract] Residual heat removal system of Fukushima Daiichi Nuclear Plant was down at 11th March 2011, because of the Tohoku Region Pacific Coast Earthquake and the Tsunami come after the earthquake. The system down causes the meltdowns in Reactor 1, Reactor2 and Reactor3. As a result, a large amount of radioactive materials were released to general environment, and dose rates of Tohoku & Kanto area increased with the fallout of the radioactive materials. Kinki University Atomic Energy Research Institute has researched time series variations of dose rate distribution and contamination level in urban distracts of Tohoku Naka-Dori Area from the middle of April 2011. Results of the researches and the analyses are described in this paper. ; Hohara, Sin-ya