Provided is an apparatus capable of distinguishing a kind of a powder deposited on an inner surface of a pipe, and more precisely measuring a thickness of the powder deposited on the inner surface of the pipe. The apparatus for measuring a thickness of a powder deposited on an inner surface of a pipe, includes a pair of the first electrodes disposed adjacent to one portion of the inner surface of the pipe and used to measure a first capacitance and thus to distinguish a kind of the powder, and a pair of second electrodes disposed in the pipe to be spaced from each other and to be symmetrical with respect to a center portion of the pipe and used to measure a second and a third capacitance.