A resin multilayer substrate includes a first resin layer, a conductive pattern that covers a portion of the first resin layer, a conductive via connected to the conductive pattern, and a second resin layer that is overlaid on the first resin layer. The second resin layer includes an opening through which the conductive pattern is partially exposed. As seen in plan view, the opening includes an inner peripheral edge including a first portion that is spaced from the conductive via by a first distance, and a second portion that is spaced from the conductive via by a second distance. The conductive pattern has a length that starts from the inner peripheral edge of the opening to outside and extends under the second resin layer. The length of the conductive pattern at the second portion is greater than the length of the conductive pattern at the first portion.