2D B-11-multiple quantum magic angle spinning NMR spectra of boron carbide were measured in order to eliminate the second-order quadrupole interaction of B-11 in B4C. Judging from the line width of MQMAS spectrum, not only the second-order quadrupole interaction but also the B-B dipole-dipole interaction was found to cause the line broadening of B4C in B-11-MAS NMR. They affect the line width in the ratio about 1.3 : 1 at spinning rate of 17 kHz.