A probe replacement method for a scanning probe microscope for measuring the surface of a sample, having a cantilever (21) having a probe (20), and a measurement unit for measuring a physical quantity between the probe and sample. The scanning probe microscope is provided with a cantilever mount (22), a cantilever cassette (30), an XY stage (14) and Z stage (15) for moving the cantilever cassette, and an optical microscope (18). In a first step, a cantilever is selected from the cantilever cassette and is mounted on the cantilever mount. In a second step, an optical microscope is moved and the mounted cantilever is set in a prescribed position in the field of view after the cantilever is mounted in the scanning probe microscope. In the second step, a step is provided for moving the optical microscope side or the cantilever side and performing positional adjustment.