Provided is a compound having an mPGES-1 inhibitory activity and useful for the prophylaxis or treatment of pain, rheumatism, osteoarthritis, fever, Alzheimer's disease, multiple sclerosis, arteriosclerosis, glaucoma, ocular hypertension, ischemic retinal disease, systemic scleroderma and cancer including colorectal cancer. A compound represented by the formula [I] or a pharmaceutically acceptable salt thereof: wherein each symbol is as defined in the SPECIFICATION.