The present invention provides a oxazole compound represented by Formula (1), or a salt thereof: wherein R1 is an aryl group which may have one or more substituents; R2 is an aryl group or a nitrogen atom-containing heterocyclic group each of which may have one or more substituents; and W is a divalent group represented by —Y1-A1- or —Y2—C(═O)— wherein Y1 is a group such as —C(═O)—, A1 is a group such as a lower alkylene group, and Y2 is a group such as a piperazinediyl group. The oxazole compound has a specific inhibitory action against phosphodiesterase 4.