A multilayer substrate includes plural layers of circuit patterns. Each circuit pattern includes a ground conductor surrounding a wiring region provided with a conductive wiring pattern. Each ground conductor includes a slit connecting between the outside of the multilayer substrate and the wiring region. In the multilayer substrate, the slit of the ground conductor provided at one of adjacent two layers of the circuit patterns and the slit of the ground conductor provided at the other circuit pattern are formed at positions not overlapping with each other. That is, these slits are formed at such positions that a view in an upper-to-lower direction is blocked. The shape of the slit of each ground conductor is in such a shape that a view from an end side of the multilayer substrate to a wiring region side is blocked.