A carboxamide compound represented by the formula (I): [wherein Q represents a nitrogen-containing 6-membered aromatic heterocyclic group optionally fused with a benzene ring, two or more ring constitutional atoms of the heterocyclic group are a nitrogen atom, and the heterocyclic group may be substituted with at least one group selected from the group consisting of a C1-C3 alkyl group etc.], and a plant disease controlling agent comprising this as an active ingredient.
