1. A left/right determination system for an arm part of a pig carcass, comprising: a clamper including a slit which has an opening oriented in a horizontal direction so that a wrist part of a pig carcass is insertable into or removable from the slit, the clamper being configured to be movable along a track in a state where the arm part of the pig carcass is suspended from the damper; a light source configured to radiate white visible light on the arm part suspended from the damper; a color imaging device configured to capture an image of the arm part being irradiated with the white visible light from an inclined horizontal direction which is inclined relative to the horizontal direction in which the opening of the slit is oriented; and a left/right determination device configured to determine whether the arm part is of a left arm or a right arm based on an image data of the arm part captured by the color imaging device, wherein the left/right determination device comprises: an output extracting part configured to extract red image signals which correspond to a red wavelength range from the image data; a first binarizing part configured to binarize the red image signals extracted by the output extracting part; and a left/right determination part configured to determine whether the arm part is of a left arm or a right arm based on the red image signals binarized by the first binarizing part.