a conductivity measuring apparatus includes a probe base having a pair of electrodes disposed on respective opposite surfaces of a portion of the probe base . observing and grasping probes are supported by the probe base in a cantilever state and are arranged adjancent to and spaced apart from one another by a predetermined distance . the grasping probe has a pair of electrodes disposed on respective opposite surfaces of a portion of the grasping probe confronting the portion of the probe base . a voltage apparatus applies a voltage between the pairs of electrodes on the probe base and the grasping probe to adjust the predetermined distance between the grasping and observing probes . a movement mechanism moves a sample base and the observing and grasping probes relative to each other to bring conductive tips of the observing and grasping probes into contact with respective contact points on a sample supported on the sample base . a measurement apparatus measures a conductivity between the contact points on the sample on the basis of a current flow generated between the conductive tips of the observing and grasping probes .