Sulfonamide derivatives represented by general formula (I) or salts thereof; insecticides for agricultural and horticultural use containing the same as the active ingredient; and usage thereof: ##STR00001## [wherein A is optionally substituted (C.sub.1 C.sub.6)alkylene, (C.sub.3 C.sub.6)alkenylene or the like; R.sup.1 is H, optionally substituted (C.sub.1 C.sub.6)alkyl, (C.sub.3 C.sub.6)alkenyl, (C.sub.3 C.sub.6)cycloalkyl or the like; R.sup.2, R.sup.3 and R.sup.4 are each H, (C.sub.1 C.sub.6)alkyl, (C.sub.3 C.sub.6)alkenyl or the like, or R.sup.2 and A or R.sup.2 and R.sup.1 may form a 3- to 8-membered ring which may be interrupted by one to three atoms selected from among O, S and N; Q is C or N; X and Y are each halogen, CN, NO.sub.2, (C.sub.1 C.sub.6)alkyl, (C.sub.2 C.sub.6)alkenyl or the like; m is 0 to 2; n is 0 to 3; and two adjacent Xs or Ys on the aromatic ring may be united to form a fused ring]. The compounds exhibit excellent insecticidal activity against insect pests resistant to existing pesticides even when applied in dosages lower than those of similar pesticides.