A circuit substrate includes a dielectric layer, a first conductive structure and a second conductive structure. The first conductive structure includes a first conductive circuit and a first conductive via. The first conductive circuit is disposed on the dielectric layer. The first conductive via is disposed in the dielectric layer, and the first conductive circuit is connected to the first conductive via. The second conductive structure includes a second conductive circuit and a second conductive via. The second conductive circuit is disposed in the dielectric layer, the second conductive circuit and the first conductive circuit of the first conductive structure are arranged with an interval, and the second conductive via surrounds the first conductive via with an interval. The second conductive structure has an extending portion. The extending portion protrudes toward the first conductive via and does not contact the first conductive via.