To shorten a measuring time without lowering measuring precision.

This image measuring instrument is provided with four imaging devices 20 for acquiring images of a specimen M, a confocal optical system 10 for imaging light from the specimen M in a view field wider than respective imaging areas of the four imaging devices 20, three mirrors 31 for changing an optical path of the confocal optical system 10, and a mirror moving origin 32 for moving the respective mirrors 31 to an optical path changing position positioned on an optical axis of the confocal optical system 10, and a retracting position retracted from the optical axis. The mirrors 31 are moved respectively to the retracting position and the optical path changing position to guide the images in the areas different each other out of the view field of the confocal optical system 10 sequentially to the plurality of imaging devices 20.