A soft key includes a main body, a shank casing, and a shank. The main body includes a compartment defined by a pair of wall tracks. The shank casing is mounted in the main body and movable along the wall tracks between a first position in the main body and a second position out of the main body. The shank is extended through a longitudinal hole of the shank casing and the compartment of the main body. The shank includes a first end positioned in the main body and a second end, a plurality of key sections being attached to the second end of the shank in series. Each two adjacent key sections are connected by a pin, thereby allowing relative pivotal movement therebetween. Each key section includes a depression in a side thereof. An outermost key section that is most distal to the shank includes at least one slanted face.