1. An X-ray target, comprising: a first cap layer; a target layer composed of a material capable of generating characteristic X-rays, said target layer formed under said first cap layer; and a second cap layer formed under said target layer; and a support block formed under said second cap layer to hold said structure, wherein a first material of which said first and second cap layers are composed is lower in electron beam absorptivity than a second material of which said target layer is composed, said target layer is buried and arranged in the form of a linear or an elliptical matrix in said first and the second cap layer, and each target layer of said matrix is made a microfocus X-ray source corresponding to its size.