Polytetrafluoroethylene porous membrane, and waterproof breathable membrane and waterproof breathable member using same

The polytetrafluoroethylene (PTFE) porous membrane according to present disclosure has a moisture permeability of 150000 g/(m 2 ·day) or more in the membrane thickness direction as measured in accordance with the specifications of JIS L1099 (B-1 Method). This PTFE porous membrane may have an average fibril length of 50 μm or more, an average node length that is at least five times of the average fibril length, and an average node area ratio of 5% or less. The PTFE porous membrane according to the present disclosure, when attached as a waterproof breathable membrane to a housing of an electrical product, an electrical component, or the like, can allow water vapor retained in the housing to be more quickly discharged out of the housing.