We have performed molecular dynamics calculations of liquid carbon disulfide and liquid benzene, intending to examine the effect of pressure on the far-infrared collision-induced absorption as well as on the local structure and on the molecular reorientational dynamics. The calculations reproduced well the experimental results of the reorientational correlation times of liquid carbon disulfide at pressures, of the reorientational anisotropy of liquid benzene, and of the density dependence of the collision-induced dipole moments and their time derivatives of both liquids. Contributions of various interaction terms to the collision-induced dipole moments were examined as a function of density. The experimental results that the collision-induced dipole moments of liquid benzene decreases and those of liquid carbon disulfide changes little with increase in density are explained well by pressure-dependent change in degree of the cancellation between the positive two-molecule interaction term and the negative three-molecule interaction terms.