To provide foamed body having heat-insulating performance and capable of readily handling a resin to be foamed, making foam content small, adjusting expansion ratio of dispersed fine foam nucleus by expansion pressure, making the pressure in foam as small as possible and reducing heat conductivity of foam when depressurized and to provide a method for producing the foam.

The foamed body has a glass transition temperature not lower than maximum service temperature under the environment using the foam and the foamed body is obtained by expanding a liquid obtained by mixing a thermosetting resin carrying out curing reaction from a liquid to a solid by heating with a gas and powder having ≤0.05 g/cm3 foam density so that foamed body density becomes ≤0.05 g/cm3. In the method for producing the foamed body, homogeneous disperse of the gas and the powder into the thermosetting resin is carried out by a stirring method utilizing revolution or rotation and represented as a planet type stirring using no stirring blade.