To provide a novel pesticide. The present invention provides a pesticide which contains, as an active ingredient, a novel pyridine derivative represented by the formula (I) or its salt: wherein R1 is alkyl, cycloalkyl, alkoxyalkyl or OR3; R2 is 1H-1,2,4-triazol-1-yl which may be substituted, 1H-imidazol-1-yl which may be substituted, 1H-1,2,3-triazol-1-yl which may be substituted, or 4H-1,2,4-triazol-4-yl which may be substituted; X is alkyl which may be substituted, cycloalkyl which may be substituted, halogen, nitro, etc.; R3 is alkyl which may be substituted, cycloalkyl which may be substituted, alkenyl which may be substituted, alkynyl which may be substituted, etc.; m is an integer of from 1 to 4.