Abstract: A vaporizer includes: a liquid storage cavity; a porous body, being in fluid communication with the liquid storage cavity to absorb the liquid substrate, and having a vaporization surface; and a resistance heating trajectory, formed on the vaporization surface and configured to heat at least a part of the liquid substrate of the porous body to generate an aerosol, where the vaporization surface is a flat plane, and includes a length direction and a width direction perpendicular to the length direction; the resistance heating trajectory includes a first end and a second end, and extends between the first end and the second end in a zigzag way in the length direction of the vaporization surface; and a distance that the first end and the second end span in the vaporization surface in the length direction is greater than 75% of a length dimension of the vaporization surface.