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.