Melanoma is a malignant tumor occurring typically in the skin. Advanced melanoma has very poor prognosis, and is also called the “king of cancer”. On the other hand, early-stage melanomas are known to be cured completely by relatively simple treatments. Therefore, early detection and treatment of melanomas is very important. However, many melanomas are still diagnosed by subjective evaluation of a physician, in other words, visual inspection. Recently, the demands for development of quantitative melanoma diagnostic technology are increasing. Much research on melanoma diagnosis has progressed in response to these demands. This review introduces some recent advances in melanoma diagnosis using spectral imaging techniques, impedance measurement and diagnostic image analysis, and also briefly describes a novel biological agent against melanoma developed in Japan. A high-quality system using multispectral imaging technique has attracted attention, but the low specificity has been regarded as a problem. It should be noted that descriptions of medical contents are limited because this review is written for engineers and researchers.