Fiber Bragg Grating (FBG) strain-sensing system has been paid much attention for the advantages of its light weight, anti-explosion, and harmlessness for electromagnetic noise, but it has not been widely used in practical applications with the high price. We have developed a new concept of wavelength meter in which the transmission center wavelength is monitored by mechanically applying a certain strain to a scanning FBG. The accuracy and stability are found to be ±0.01 nm for 12 days running, which is enough for the most applications.