A device for a bimodal diagnostic probe with optical and ultrasonic imaging, the probe including a main body supporting an ultrasonic transducer at its front end. The device includes a shell, an illumination mechanism mounted on a front end of the shell to light outside of the shell, and a collection or detection mechanism mounted on the front end of the shell to collect or detect an optical signal produced outside the shell. The shell includes an attachment mechanism to reversibly assemble it around the main body of the probe, with the illumination mechanism and the collection or detection mechanism mounted on the shell.