A scanning probe microscope has a cantilever having a minute probe on a distal end thereof and a displacement detecting device for detecting displacement of the cantilever. The signal connector includes the reverse tapered mounting tab coupled to a connector body having a connector port inside. The second and third pads are made of a same material and have substantially a same thickness, and the layers of insulating material have a same thickness too. The second spring is oriented such that its in-plane dimension is aligned with the length of the first spring’s serpentine structure. Moreover, the sectional shape is such that if an angle formed between the substrate and the tangent of the sectional shape at an intersection of the curve and a normal with respect to the substrate respectively extended from the light emission element and the light-receiving element is designated as, the critical angle of the light-guiding portion material becomes larger than 180-2. According to policy, the user directly contacts the peers on the second list received from the IPIS to inform those peers the user is currently signed on-line.