To provide an SPM probe comprising an SPM probe having a piezoresistor and enable to measure surface voltage of a sample. An SPM probe forming a piezoresistor 20 has conductivity covering metal film 22 on a tip surface 12, and conductive layer 24 is wired from the metal film 22 so as to be one side of an electrode. By that, it is possible to measure interaction between the sample surface by detecting bending quantity of the SPM probe by the piezoresistor and the tip, and to measure voltage of the sample surface without using a detector needing complicated adjustment.