Measuring sheet, measuring device, and measuring method

The invention provides a measuring sheet, a measuring device and a measuring method. A measurement sheet is provided with: a propagation layer through which light propagates; an introduction unit that introduces the light to the propagation layer; a lead-out unit that leads out the light from the propagation layer; and a reaction part which is formed on the surface of the propagation layer and is a region in which a reaction substance that reacts with a substance to be detected is immobilized, and which is formed in the surface of the propagation layer from the introduction part to the discharge part. The content of the reactive substance increases or decreases across a prescribed length in the direction of propagation of the light in a vertical direction orthogonal to the direction of propagation of the light. 提供测量用片、测量装置及测量方法。测量用片具备：传播层，供光传播；导入部，向所述传播层导入所述光；导出部，从所述传播层导出所述光；以及反应部，形成在所述传播层的表面，是与被检测物质反应的反应物质被固定的区域，在所述反应部中，从所述导入部直到所述导出部，所述反应物质的含量在与所述光的传播方向正交的垂直方向上跨所述光的传播方向的规定的长度而增加或者减少。