An operator's cab includes an operator's seat provided on a floor surface, a control lever that is provided laterally to the operator's seat and is operated at least toward the operator's seat, and an armrest that includes an upper surface and is provided laterally to the operator's seat in the rear of the control lever. A front portion of the upper surface is larger in width than a rear portion of the upper surface. The front portion of the upper surface includes an inclined portion. With the floor surface being defined as the reference, the inclined portion decreases in height toward the operator's seat.