Provided are: a polyetherimide porous body which has a low relative permittivity and is not easily cracked (or is excellent in cracking resistance) when folded, and a method for producing the porous body. This polyetherimide porous body comprises a polyetherimide crosslinked body and has a gel fraction of 10% or more, an average cell diameter of 8 μm or less, a volume porosity of 30% or more and an insulation breakdown voltage of 30 kV/mm or more.