To obtain cross-linked rubber particles capable of forming impact resistance-improving materials or impact-resistant resins having excellent impact resistance, especially low temperature impact resistance, and useful for impact- resistant moldings, etc., by compounding an isobutylenic polymer component and an organosilaxane-based polymer component.

The cross-linked rubber particles comprise (A) an isobutylenic polymer component [for example, a polymer component containing isobutylene- originated units in an amount of ≥50 wt.% and having halogen-containing groups, radically reactive unsaturated groups (concretely groups originated from a conjugated dienic monomer, etc.), or silicon-containing groups at the molecular terminals or in the molecular chain], (B) an organosiloxane-based polymer component, and, if necessary, (C) a vinylic polymer component. The particles preferably comprise the components A, B and C in amounts of 1-99 wt.%, 1-99 wt.% and 0-90 wt.%, respectively, and are preferably controlled to a gel content of ≥20 wt.% and an average particle diameter of 0.05-10 μm.