Mesoporous carbon with homogeneous boron dopant was prepared by co-impregnation and carbonization of sucrose and boric acid confined in mesopores of SBA-15 silica template. Low-level boron doping shows catalytic effect on oxygen chemisorption at edge planes and alters electronic structure of space charge layer of doped mesoporous carbon. These characteristics are responsible for substantial improvement of interfacial capacitance by 1.5-1.6 times higher in boron-doped carbon than that in boron-free carbon with alkaline electrolyte (6 M KOH) and/or acid electrolyte (1 M H₂SO₄). This finding should be very useful for developing new doped carbon electrode materials for supercapacitors.