A multilayer wiring board includes: a multilayer body including a plurality of insulating layers; a lower outer electrode provided on a lower surface of the multilayer body; a first via conductor connected at one end to the lower outer electrode; a first in-plane conductor connected to another end of the first via conductor; a second via conductor provided within the multilayer body on a surface of the first in-plane conductor on the opposite side from a surface of the first in-plane conductor in a position distanced from the first via conductor viewed in a direction orthogonal to a layering direction of the multilayer body, one end of the second via conductor being connected to the first in-plane conductor; and a second in-plane conductor connected to another end of the second via conductor. A line width of the first in-plane conductor is narrower than that of the second in-plane conductor.