An RF power sensor for measuring power for an RF signal using capacitance includes a substrate preferably formed of a semiconductor, such as silicon or of a dielectric substance, a fixture part fixed to the substrate and forming a signal line and ground lines that transmit RF signals, and a bridge connected to the ground lines and floating over the signal line, wherein the bridge is driven by an external driving force, and the external driving force induces capacitance between the bridge and the signal line. Accordingly, power for an RF signal can be measured through the capacitance between the signal line and the bridge. The RF power sensor facilitates matchings, reduces insertion loss, and can be used in a wide bandwidth because it is based on transmission lines having characteristic impedance. Further, high power can be measured depending upon bridge designs.