Patent Number: 
Section: claims

1. A detection apparatus for detecting the surface of a specimen by means of a cantilever having a probe and a piezo resistance element comprising: a first circuit for detecting an electric current flowing through said piezo resistance element; and  a second circuit for detecting through said probe an electric current flowing between said probe and said specimen;  wherein the electric current flowing through said piezo resistance element and the electric current flowing between said probe and said specimen are detected by way of a common current path. 2. A detection apparatus according to  claim 1 , wherein claim 1 said first circuit includes a means for applying a predetermined voltage to said piezo resistance element and a means for applying a predetermined voltage to said specimen. 3. A detection apparatus according to  claim 2 , wherein claim 2 said first circuit further includes a means for removing offset components from the detected current signal. 4. A detection apparatus according to  claim 3 , further comprising: claim 3 a switch means for separating said means for removing offset components from said common current path when detecting the electric current by means of said second circuit. 5. A detection apparatus according to  claim 3 , wherein claim 3 said means for removing offset components includes a voltage source for generating a constant voltage and a variable resistor and removes said offset components by adjusting said variable resistor. 6. A detection apparatus according to  claim 1 , wherein claim 1 said electric current detected by said second circuit is a tunnelling current. 7. A detection apparatus according to  claim 2 , wherein claim 2 a predetermined voltage is applied to said specimen in order to remove an electric current flowing into said common current path by way of said probe when detecting the electric current flowing through said piezo resistance element. 8. A detection apparatus according to  claim 7 , wherein claim 7 said voltage applied to said specimen is set to a half of the voltage applied to said piezo resistance element. 9. A detection apparatus according to  claim 2 , being so designed that no voltage is applied to said piezo resistance element when detecting the electric current flowing between said probe and said specimen. claim 2 10. An observation apparatus comprising a detection apparatus according to any one of claims  1  through  9 . 11. An observation apparatus according to  claim 10 , claim 10 further comprising a plurality of said cantilevers;  a probe array unit having a plurality of said detection apparatus provided for each of said cantilevers; and  a control means for controlling said probe array unit. 12. An observation apparatus according to  claim 11 , wherein claim 11 said control means conducts the selection of a probe to be used for measurement and the setup of the corresponding detection system. 13. A detection method for detecting the surface of a specimen by means of a cantilever having a probe and a piezo resistance element, comprising the steps of: detecting an electric current flowing through said piezo resistance element; and  detecting an electric current flowing between said probe and said specimen; wherein the electric current flowing through said piezo resistance element and the electric current flowing between said probe and said specimen are detected by way of a common current path. 14. A detection method according to  claim 13 , wherein claim 13 a predetermined voltage is applied to said specimen in order to remove the electric current flowing into said common current path by way of said probe when detecting the electric current flowing through said piezo resistance element. 15. A detection method according to  claim 14 , wherein claim 14 said voltage applied to said specimen is set to a half of a voltage applied to said piezo resistance element. 16. A detection method according to  claim 13 , wherein no voltage is applied to said piezo resistance element when detecting the electric current flowing between said probe and said specimen. claim 13 17. A detection method according to  claim 13 , wherein claim 13 offset components are removed from said detected current signal flowing through said piezo resistance element by means of an offset-removing circuit. 18. A detection method according to  claim 17 , wherein said offset-removing circuit is separated from said common current path when detecting the electric current flowing between said probe and said specimen. claim 17 19. An observation method comprising a detection method according to any one of claims  13  through  18 . 20. An observation method according to  claim 19 , wherein claim 19 said cantilever is of a multiple type having a plurality of cantilevers and said detection method is conducted independently for each of the cantilevers.