We experimentally demonstrate a simple modulation-free scheme for offset locking the frequency of a laser using buffer gas-induced resonance. Our scheme excludes the limitation of low diffraction efficiency and laser input intensity when an acousto-optic modulator is applied to shift the laser frequency from the resonance. We show the stabilization of a strong 795-nm laser detuned up to 550 MHz from the 87Rb 5S1/2F=2->5P1/2 F'=2 transition. The locking range can be modified by controlling the buffer gas pressure. A laser line width of 2 MHz is achieved over 10 min.