An electronic atomization device, and an atomizer and a heating assembly thereof. The heating assembly includes a porous body and heating element. The porous body includes a porous body configured to suck liquid medium and a heating element configured to heat and atomize the liquid medium sucked in the porous body; the porous body includes a first surface and a second surface opposite to the first surface, and the first surface is an atomization surface configured to mount the heating element. The second surface is recessed inwards to form a liquid guiding hole configured to receive a liquid guiding element, the liquid guiding hole has a bottom surface, a projection region of the bottom surface projected on the atomization surface is defined as a core atomization region, and the core atomization region is a region in which the heating element is intensively distributed.