A bone cement apparatus is provided. The complex membrane includes a micro-porous polyolefin membrane, and a web-phase porous membrane united to at least one side of the micro-porous polyolefin membrane and composed of nano-fibers. The stator includes a plurality of stator laminations each having a winding wound therearound, and a shaft having opposite ends fixed with the upper partition and the lower partition. The frequency control circuit varies the reference signal to change the frequency of the signal output from the oscillator. In this case, the rear lens unit has a first lens component with positive refracting power and a second lens component with negative refracting power so that an aspherical surface is not included in any lens component, and satisfies the following conditions:.