We propose a forced chaos generator with a CMOS variable active inductor circuit. Two values of the equivalent inductance of the active inductor in the proposed circuit are switched by an external periodic square-wave voltage, so that a stretching-and-folding mechanism of chaotic motion is realized. The chaotic dynamics are confirmed through SPICE simulations with TSMC 0.35 μm CMOS semiconductor process parameters. Moreover, we present bifurcation phenomena, which are generated when the amplitude and the period of the external signal are changed as bifurcation parameters. A prototype chip for the proposed circuit was designed and fabricated with TSMC 0.25 μm CMOS semiconductor process.