A container commonly usable for electromagnetic cooking heaters and microwave ovens. A resin container commonly usable for electromagnetic cooking heaters and microwave ovens having an aluminum thin, film on the bottom thereof for storing food therein. The aluminum thin film is 5 30 .mu.m in thickness and 70 cm.sup.2 in area, and has no projections having a curvature radius of less than 2 cm over the entire surface thereof. The aluminum thin film covers 30 80% of the bottom area of the container.