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.