The structure of porous silicon carbide has been studied using transmission electron microscopy both in planar geometry and in a cross-section of a porous film. Peculiar structures in the form of shared rosettes with petals of about 3-8 m in size and a density of were found in the subsurface layer. These formations are pierced by thin channels (pores) with an average diameter of 10 nm. Near the surface of the layer the channels in the `lobes' may be directed at small angles to the surface, but, with increasing depth, all of them become approximately perpendicular to the surface, with branching observed. On channel walls there is a rather thick layer of fine particles with characteristic dimensions of the order of 0.8-1.0 nm. Spectral cathodoluminescence studies have been performed with luminescence excited by a narrow (2 m) electron probe on parts of the initial sample and porous film having varied thickness (0.03-3 m). A layered structure was revealed in the porous film, with the layer responsible for the `blue' luminescence band ( eV) due to the presence of fine crystallites located at a certain depth, rather than immediately near the surface.