An image capturing device unit includes a multilayer substrate, an image capturing device mounted on one face of the multilayer substrate, and components mounted on the other face of the multilayer substrate. The multilayer substrate includes electrodes to electrically connect the image capturing device and the multilayer substrate, vias that electrically connect the electrodes and the components, first wiring electrically connected to the vias, second wiring on layers of the multilayer substrate, and a non-wired region that insulates the vias and the first wiring from the second wiring on each of the layers. The vias are located in the multilayer substrate so that, on a projection plane given when the multilayer substrate is viewed in a layering direction of the multilayer substrate, there is no area in which the non-wired region overlaps with a region where the image capturing device is arranged throughout the layers.