The objective of this research is to examine the esophageal tissues by means of absorption spectra, and to develop new techniques for the diagnostics of esophageal cancer. A two-dimensional absorption-spectrum measurement system was designed. A xenon lamp (230-700 nm) was used as a broadband light source in the visible region. By the use of a two-axis translation stage, the system can perform a two-dimensional scan. The spectrum measurement system is in a transmitted type. We also developed algorithms to analyze the correlation of spectra and to evaluate the possibility of malignancy of a tissue. The absorption spectra of three sets of both normal and cancerous esophageal tissues were measured. We defined the standard absorption spectra of normal and cancerous esophageal tissues with the analysis of the correlation between different spectra. Furthermore, we evaluated the possibility of malignancy of each tissue with the standard spectra and the developed algorithms.