The present invention provides: a cationic natural rubber latex comprising cationic natural rubber microparticles in which the surfaces of natural rubber microparticles are coated by a cationic polymer, a weight average molecular weight of the cationic polymer being from 3000 to 150000, a concentration of the cationic natural rubber being from 30 to 70% by mass, a viscosity at 20° C. being 500 mPa·s or less, and surface potential of the cationic natural rubber microparticles being −3 mV or less; and a tire puncture sealant comprising the cationic natural rubber latex and an acidic resin emulsion, a mass ratio of a solid content of the cationic natural rubber latex to a solid content of the acidic resin emulsion being from 90:10 to 10:90. Such tire puncture sealant has superior puncture-sealing ability, storage stability, and workability.