A heterocyclic compound having an RORγt inhibitory activity, which is a compound of formula (I) or a salt thereof is provided. The compound has ring A, which is an optionally substituted cyclic group and is bound to a pyrazole ring though Q. Q is a bond, optionally substituted C1-10 alkylene, optionally substituted C2-10 alkenylene, or optionally substituted C2-10 alkynylene. R1 is a substituent. Ring B is a thiazole ring, an isothiazole ring or a dihydrothiazole ring, each of which is optionally further substituted by a substituent in addition to R2. R2 is an optionally substituted cyclyl-carbonyl-C1-6 alkyl group, an optionally substituted aminocarbonyl-C1-6 alkyl group, an optionally substituted cyclyl-C1-6 alkyl group, an optionally substituted cyclyl-C1-6 alkylamino-carbonyl group, an optionally substituted aminocarbonyl-C2-6 alkenyl group, an optionally substituted C1-6 alkylcarbonylamino-C1-6 alkyl group, an optionally substituted cyclyl-aminocarbonyl group, an optionally substituted cyclyl-carbonyl group or an optionally substituted non-aromatic heterocyclic group.