The present invention provides a oxazole compound represented by Formula (1), or a salt thereof:
wherein R
1
is an aryl group which may have one or more substituents; R
2
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 —Y
1
-A
1
- or —Y
2
—C(═O)— wherein Y
1
is a group such as —C(═O)—, A
1
is a group such as a lower alkylene group, and Y
2
is a group such as a piperazinediyl group. The oxazole compound has a specific inhibitory action against phosphodiesterase 4.