To provide a heterogeneous catalyst that exhibits high activity and high selectivity, specifically a catalyst suitable for oxychlorination to produce 1,2-dichloroethane from ethylene, and a catalyst system. Provided are: a heterogeneous catalyst supported on a porous carrier, characterized in that the integral value of the hysteresis occurring between an adsorption isotherm and a desorption isotherm by a gas adsorption method, is at most 19% to the total integral value of the adsorption isotherm; and a catalyst system for producing 1,2-dichloroethane, which comprises this catalyst and a diluent having a spherical shape, circular cylindrical shape or hollow cylindrical shape.