A rubber composition of the present technology for a conveyor belt contains a diene rubber and a carbon black, the diene rubber containing: a natural rubber; and a modified butadiene rubber obtained by modifying a butadiene rubber with a nitrone compound; the content of the natural rubber in the diene rubber being 30 to 85 mass %, and the content of the modified butadiene rubber in the diene rubber being 15 to 70 mass %.