There is provided a hydraulic excavator allowing a simple configuration to be employed to determine a posture of a work implement accurately. The work implement and an imaging device are attached to a revolving unit. The work implement operates on a prescribed operating plane. The imaging device captures an image of the work implement at an angle larger than 0° with respect to the operating plane. The controller determines a position of the work implement relative to the revolving unit based on a posture of the work implement in the image captured by the imaging device.