A carboxylic acid compound represented by formula (I): 1 (meanings of the symbols in the formula are as mentioned in the specification) and a pharmaceutical agent comprising the compound. Since the compound represented by formula (I) binds to a DP receptor and shows antagonistic activity for the DP receptor, it is useful for prevention and/or treatment of diseases such as allergic disease (such as allergic rhinitis, allergic conjunctivitis, atopic dermatitis, bronchial asthma and food allergy), systemic mastocytosis, disorders accompanied by systemic mast cell activation, anaphylaxis shock, bronchoconstriction, urticaria, eczema, diseases accompanied by itch (such as atopic dermatitis and urticaria), diseases (such as cataract, retinal detachment, inflammation, infection and sleeping disorders) which is generated secondarily as a result of behavior accompanied by itch (such as scratching and beating), inflammation, chronic obstructive pulmonary diseases, ischemic reperfusion injury, cerebrovascular accident, chronic rheumatoid arthritis, pleurisy, ulcerative colitis and the like.