Provided are: a silicone gel composition providing a silicone gel cured product having excellent heat resistance at high temperatures; and a cured product (silicone gel) thereof.This silicone gel composition is an addition reaction-curable silicone gel composition containing, with respect to the total (mass) of the composition, 1-1,000 ppm of a niobium carboxylate and/or nickel carboxylate represented by the following formula (3). (R3COO)fM  (3) (In the formula, R3 is a homogeneous or heterogeneous monovalent hydrocarbon group, M is at least one metal selected from among nickel and niobium, and f is 2 when M is nickel and 4 or 5 when M is niobium).