Using a pressure-pulsed chemical vapor infiltration technique, SiC was infiltrated from a SiCl4 (4%)-CH4 (4%)-H-2 gas phase into carbonized paper preforms at 1100degreesC. SiC-based cellular substrates with cell wall thicknesses of 25, 50 and 100 mum were obtained by using honeycomb-shaped paper preforms as the templates. The reduction of both wall thickness t and cell pitch d of SiC-based honeycomb substrate successfully led to an increase in geometric surface area per unit volume S, keeping pressure drop DeltaP at constant, besides; DeltaP decreased without lowering S by the reduction of t and the increase in d. The pressure drop in the prepared honeycomb substrates depended on S(2)alpha(-3) value, where alpha was open frontal area fraction. The compressive strength of the honeycomb substrates with t of 25 mum was about 7 MPa. The strength increased in proportion with 1 - alpha, which corresponded to the volume fraction of the cell wall in the honeycomb substrate.