Abstract: An object detecting device for detecting an object at least partly having a magnetic substance or magnetic-flux permeable material is formed of a detection coil arrangement including a primary coil for generating magnetic flux and a secondary coil disposed separately from the primary coil at a predetermined interval for receiving the magnetic flux from the primary coil; and a detection circuit for detecting an increase of the magnetic flux transmitted to the secondary coil due to presence of the object within a space between the primary and secondary coils. The detection circuit produces signal indicating the presence of the object upon detection of the presence.