The Fukushima Prefecture and neighboring areas in northeast Japan were severely polluted by radioactive leakage at the Fukushima nuclear power plant caused by an earth quake. Because we had no experience dealing with such large scale accidents, it became necessary to determine immediately the real extents of the contamination. Air dose and surface contamination density measurements were conducted in a park in Fukushima City to determine the actual levels of radioactive contamination. The results showed that the air dose levels at the park were 0.99 - 3.2μSv/h. In addition, several radioactive hot spots were found, and comparatively larger doses and surface contaminations were found on benches and playground equipment.