A support base for an electronic device includes a base, a trigger mechanism and an operating mechanism. The base includes a limit rib. The trigger mechanism includes a trigger member and a swing member. The trigger member is movably disposed on the base and therefore has an untriggered position and a triggered position. The swing member is pivoted on the trigger member and therefore has a pressed position and a room-making position. The operating mechanism is movably disposed on the base and therefore has a first operating position and a second operating position. The operating mechanism has an operating end and a moving end opposite to each other. The moving end corresponds to the swing member and is used for rotating relative to the operating end. When the operating mechanism is at the first operating position, the moving end of the operating mechanism is hooked at the limit rib.