In this paper, a novel probe with an integrated radio frequency single-electron transistor (rf-SET) for magnetic resonance force microscopy operated at low temperatures is proposed and fabricated. By using the charge sensitivity of the rf-SET, the displacement of a cantilever can be detected from the capacitance variation between the quantum island and the gate formed on the cantilever with high sensitivity. The rf-SET using a Cr thin film isolated with tunneling junction of a thin silicon dioxide film was fabricated on the basis of electron beam lithography and self-aligned island formation.