An imaging and displaying system comprises an imaging unit for acquiring images of a treatment site of a subject, a display unit for displaying the images acquired by the imaging unit, and a unit-to-unit connecting device for detachably connecting the imaging unit and the display unit. The imaging unit and the display unit are spatially and movably supported. At least one of the imaging unit and the display unit is detachably attached to an arm with a unit-to-arm detachable device therebetween.