Objective: A scanning acoustic microscope (SAM) is a device that uses ultrasound (frequency, >20 kHz) to image an object or tissue. Because it is known that the harder the tissue, the more the speed of ultrasound, SAM can provide data on the elasticity of cells and tissues. Method: We compared lymph node lesions between acoustic and light microscopic images to evaluate the usefulness of SAM. Results: SAM system discriminated lymph node components and demonstrated distinct acoustic images of the lymph nodes such as cancer metastasis, lymphomas, granulomatous diseases, and deposition diseases such as amyloidosis. Areas with desmoplastic reactions associated with cancer invasion or post-inflammatory fibrosis showed the greater speed of sound than normal lymph nodes. These results corresponded well to those obtained using the conventional microscope.