Recent advances in fluorescence confocal endomicroscopy have allowed real-time identification of residual tumour cells on the walls of the cavity left by breast conserving surgery. However, it is difficult to systematically survey the surgical site because of the small imaging field-of-view of these probes, compounded by tissue deformation and inconsistent probe-tissue contact when operated manually. Therefore, a new robotized scanning device is required for controlled, large area scanning and mosaicing. This paper presents a robotic scanning probe with an inflatable balloon, providing stable cavity scanning over undulating surfaces. It has a compact design, with an outer diameter of 4 mm and a working channel of 2.2 mm, suitable for a leached flexible fibre bundle endomicroscope probe. With the probe inserted, the tip positioning accuracy measured to be 0.26 mm for bending and 0.17 mm for rotational motions. Large area scanning was achieved (25-35 mm(2)) and the experimental results demonstrate the potential clinical value of the device for intraoperative cavity tumour margin evaluation.