A device according to an embodiment includes an optical system employing the OCT, and tomographically visualizes the viscoelasticity of tissue of an object. The device includes an optical mechanism that guides light from a light source to the tissue of the object to scan the tissue, a loading device that applies deformation energy to the tissue, a control computation unit that computes tomographic distribution of the viscoelasticity of the tissue by controlling driving of the loading device and the optical mechanism and processing an optical interference signal from the optical system on the basis of the driving, and a display device that displays the viscoelasticity of the tissue in a form of tomographic visualization. The loading device is a non-contact loading device that loads acoustic radiation pressure in the tissue by outputting ultrasonic waves toward a focus point set in the object.
