A thermally conductive sheet has cut surfaces with low surface roughness and hence shows reduced thermal resistance at the interfaces, and high thermal conductivity in the thickness direction. Thus, the thermally conductive sheet can be interposed between any of various heat sources and a radiation member. The process for producing the thermally conductive sheet includes at least: an extrusion molding step in which a thermally conductive composition containing a polymer, an anisotropic thermally conductive filler, and a filler is extruded with an extruder to thereby mold an extrusion-molded product in which the anisotropic thermally conductive filler has been oriented along the extrusion direction; a curing step in which the extrusion-molded product is cured to obtain a cured object; and a slicing step in which the cured object is sliced into a given thickness with an ultrasonic cutter in the direction perpendicular to the extrusion direction.