This invention relates to a VLA-4 inhibitory drug, having good oral absorbability and exhibiting sufficient anti-inflammatory effects when administered orally, wherein an active ingredient is represented by formula (I), or a salt thereof:Q represents an optionally-substituted monocyclic or bicyclic nitrogen-containing heterocyclic group having a nitrogen atom as the bonding site； Y represents an oxygen atom or CH2； W represents an optionally-substituted bicyclic aromatic hydrocarbon ring group or an optionally-substituted bicyclic aromatic heterocyclic group； A1 represents a nitrogen atom or C—R3d wherein R3d represents a hydrogen atom, a halogen atom, a C1-8 alkoxy group or a C1-8 alkyl group； R1 represents H or a C1-8 alkyl group； R2 represents H, a halogen, a C1-8 alkoxy
