A rolling-ball switch includes a surrounding wall defining an axial hole and including two opposite open ends, and two metallic terminals plugged in the axial hole respectively from the open ends. The surrounding wall has an inner surface formed with two spaced-apart first annular recesses proximate to the open ends, respectively, and two spaced-apart second annular recesses respectively adjacent to the first annular recesses but distal from the respective open ends. Each terminal has an insert portion inserted into the axial hole, and axially spaced-apart first and second barbed surfaces formed annularly around the insert portion. The first barbed surface is engaged to a respective first annular recess. The second barbed surfaces of the metallic terminals are engageable respectively with the second annular recesses when the terminals expand due to heat. A ball member is disposed rollably in the axial hole to contact the terminals.