A bulb socket and bulb arrangement includes a jacket set at a caulking part above the fixture of the bulb socket. There are several jack catches inside the jacket. The outer part of the bulb has several convex catches. When the bulb is inserted into the bulb socket, the convex catches of the bulb will be geared between the jack catches within the jacket. Such an engagement can fix the bulb with the fixture of the bulb socket more effectively.