A device and a method for making a tire puncture sealant having a higher concentration of propylene glycol are disclosed, wherein the device comprises: a container having a cylindrical space for a mixed solution of rubber latex and a tackifier; a squirter comprising at least one spout for pouring propylene glycol on the surface of the mixed solution in the container at a rate of 0.01 to 1.0 liter/minute per spout; and an agitator for the mixed solution in the container, comprising a stirring blade rotatable in the mixed solution to cause said surface a current speed of the mixed solution in a range between about 1.0 and about 10.0 meter/second during pouring the propylene glycol.