Provided is a three-dimensional (3D) transmon qubit apparatus including a body portion, a driver, a transmon element disposed in an internal space of the body portion, a first tunable cavity module disposed in the internal space of the body, and comprising a first superconductive metal panel; and a second tunable cavity module disposed in the internal space of the body, and comprising a second superconductive metal panel, wherein the transmon element is disposed between the first superconductive metal panel and the second superconductive metal panel; wherein the first tunable cavity module and the second tunable cavity module are configured to adjust a distance between the first superconductive metal panel and the second superconductive metal panel, and wherein the driver is configured to tune a resonance frequency by adjusting a 3D cavity by adjusting the distance between the first superconductive metal panel and the second superconductive metal panel.