A pest control agent containing a nitrogen-containing heterocyclic derivative which has a 2-imino group, which is represented by the following Formula (I), or salts thereof, ** ** Formula in formula Ar represents a phenyl group which may be substituted with any of a halogen atom, C1 to C4 alkyl group which may be substituted with a halogen atom, an alkyloxy group C1 to C4 alkyl which may be substituted with a halogen atom, a hydroxyl group, a cyano group, a nitro group a 5- to 6-membered can be substituted with any of a halogen atom, a C1 to C4 alkyl which may be substituted with a halogen atom, an alkyloxy group C1 to C4 alkyl which may be substituted with a halogen atom, a hydroxyl group , a cyano group and a nitro group or a heterocycloalkyl group of 4 to 10 membered ring represented by the following Formula: Formula ** ** represents any one of the rings represented by the following formulas (A-1) to (A-40): Formula ** * Y represents a hydrogen atom, a halogen atom, a hydroxyl group, a C1 to C6 which may be substituted with a halogen atom, an alkyloxy group C1 to C6 which may be substituted with a halogen atom, a cyano group or 1 may nitro group, and R represents a group represented by the following Formula (c) ** ** Formula wherein R3 represents a C1 to C6 alkyl which may be substituted with a halogen atom.Un agente de control de plagas que contiene un derivado heterocíclico que contiene nitrógeno y que tiene un grupo 2-imino, que está representado por la siguiente Fórmula (I), o sales del mismo,**Fórmula** en la fórmula Ar representa un grupo fenilo que puede sustituirse con cualquiera de un átomo halógeno, un grupo alquilo C1 a C4 que puede estar sustituido con un átomo halógeno, un grupo alquiloxi C1 a C4 que puede estar sustituido con un átomo halógeno, un grupo hidroxilo, un grupo ciano, un grupo nitro un heterociclo de 5 a 6 miembros que puede sustituirse con cualquiera de un átomo halógeno, un grupo alquilo C1 a C4 que puede estar sustituido con un átomo
