Electromagnetic shielding carbon nanotube/polymer composite material, electromagnetic shielding material, and method for producing electromagnetic shielding carbon nanotube/polymer composite material

Provided is an electromagnetic shielding carbon nanotube (CNT)/polymer composite material having excellent electromagnetic shielding performance. This electromagnetic shielding CNT/polymer composite material has a film thickness of 0.1-10 5 µm inclusive, contains CNTs having a diameter of 20 nm or less and consisting of 10 or less layers, and includes 0.1-80 inclusive parts by weight of the CNTs with respect to the total weight of an elastomer or polymer. The CNTs constitute a continuous network in the elastomer or polymer. When kept for 6 hours under a nitrogen environment at a temperature of 400°C or higher, the elastomer or polymer thermally decomposes and the remaining CNTs form a structure. Va/V 0 is 0.5 or greater, where V 0 is the initial volume of the composite material and Va is the volume of the remaining CNT structure. The pore distribution of the remaining CNT structure has a dV/dlog(d) value of 0.6 or less in the range of 0.5-10 µm inclusive. The remaining CNT structure has at least one peak between 10 nm and 10 µm inclusive. This composite material has a shielding ability of 0.1×10 -1 db/µm or greater against electromagnetic waves having arbitrary wavelengths in the frequency range of 100 Hz to 1 THz inclusive.