電子微探儀係利用聚焦電子束進行微區分析之電子顯微鏡，其分析方式與一般常見的能量散佈光譜儀相似，但其運作原理則截然不同。電子微探儀是藉由分析特徵X光的波長以辨別元素，其具有較佳的峰值∕背景 (P/B) 比，故可進行較精確的定量分析，其準確度可達100 ppm。本文將先介紹電子微探儀的發展與原理，再說明其分析方式與應用。

Electron probe microanalyzer (EPMA) is a scanning electron microscope which employs the focused electron beam to analyze the composition in a micro region. The analysis method of EPMA is similar th the commercial energy dispersive spectrometer (EDS). However, the operation principle is entirely different from EDS. The theory of EPMA is to analyze the wavelength of characteristic X-ray to evaluate the element concentration. The quantitative analysis can be carried out by EPMA due to the good P/B ratio of spectrum with the resolution better than 100 ppm. In this article, the development and theory of EPMA are revealed, and then the analysis methods and applications are also described.