Abstract: A tablet, a gas generator and a gas generating device are provided, wherein the tablet comprise a tablet body, the tablet body comprises opposite first and second sides, the tablet body is provided with a vent hole running from the first side to the second side, the first side is provided with a first positioning structure, and the second side is provided with a second positioning structure that cooperates with the first positioning structure. By the smart design of the tablet structure, the present disclosure can effectively simplify the structure of the gas generator and reduce the manufacturing cost.