The present invention provides a liquid state detecting sensor that is free from a problem of increase in the number of parts and a problem in assembly and furthermore capable of, in support of electrodes, absorbing an error and supporting both electrodes, even in case an inner electrode has at a surface an insulation layer, without causing any damage to the layer. The liquid state detecting sensor includes an outer tubular electrode 10 shaped tubular and formed from a conductor, an inner electrode 20 in the form of a shaft and disposed along an axial direction G and within the outer tubular electrode, and a base end support member 40 that supports, at base end sides of the both electrodes 10 and 20, the both electrodes 10 and 20 while holding the electrodes insulated from each other, and detects a level of liquid within a tank 1, etc. by measuring an electrostatic capacity between the electrodes, wherein an elastic body 30 made of rubber is disposed, by insertion under pressure, at a place outside a leading end or its adjacent portion of the inner electrode 20 and inside the outer tubular electrode 10. Since the leading end or its adjacent portion of the inner electrode 20 is elastically supported on an inside of the outer tubular electrode 10, the assembly can be attained with ease and the dimensional error of the parts and vibrations thereof can be absorbed.