To provide a PTFE (polytetrafluoroethylene) porous body which can keep a high porosity and has excellent tensile strength, and also to provide the insulated wire and cable using the PTFE porous body as an insulating material.

There is provided a PTFE porous body which is made to be porous without using a drawing method by removing a foaming agent and exhibits an endothermic phenomenon in the range of 370 to 390°C. There is also provided an insulated wire in which an insulated body comprising the PTFE porous body is formed on the periphery of a central conductor, and is moreover provided a coaxial cable comprising the insulated wire and an external conductor formed on the periphery of the insulated body of the above insulated wire.