A controller assembly includes a base plate, a bracket, and a first controller main body. The base plate includes a through hole and a frame having an upper surface and a lower surface and surrounding the through hole. The bracket has first and second flange portions supported on the upper surface of the frame at positions opposite to each other over the through hole, first and second side portions coupled respectively to the first and second flange portions and passing through the though hole; and a bottom portion coupled to both of the first and second side portions on the side of the lower surface of the frame. The first controller main body is mounted on a bottom portion of the bracket. Accordingly, a controller assembly which can be readily assembled, a cab of a work implement, and a work machine can be obtained.