PURPOSE: To provide a surface shape measuring instrument which has a small size and a small mass of driving section and can be controlled at a high speed.

CONSTITUTION: A probe is provided at the free end of a spring member 2 so that the probe 1 is opposed to a sample 3 and the fixed end of the member 2 is held by means of a driving element 4 which is controlled by the output of a controller 8. A projector 7 is constituted of a light source and optical member so that the projector 7 can project light upon the free and fixed ends of the member 2 and photodetecting elements 10 and 6 are arranged so that the elements 10 and 6 can receive two light beams reflected from both ends of the member 2. The outputs of the elements 10 and 6 are inputted to a differentiating device 9 and the output of the device 9 is inputted to the controller 8. A driving element 5 slightly moves three-dementionally while driving element 5 holds the sample 3.