A rubber composition includes a sulfur-crosslinkable diene rubber, from 1 to 100 parts by mass of carbon black and/or from 5 to 150 parts by mass of an inorganic filler, from 0.5 to 30 parts by mass of a sulfur-containing compounding agent, and from 0.01 to 20 parts by mass of a phosphine borane compound based on 100 parts by mass of the sulfur-crosslinkable diene rubber. The rubber composition may be applied in at least one type selected from the group consisting of a capped tread, a side wall, a belt, an inner liner, a carcass, and a bead of a pneumatic tire.