Development of terahertz (THz) and long-wave infrared (LWIR) technologies is mainly bottlenecked by the limited intrinsic response of traditional materials. Hyperbolic phonon polaritons (HPhPs) of van der Waals semiconductors couple strongly with THz and LWIR radiation. However, the mismatch of photon−polariton momentum makes far-field excitation of HPhPs challenging. Here, we propose an In-Plane Hyperbolic Polariton Tuner and demonstrate a first device responding to direct far-field excitation and giving rise to a unique set of characteristic functions at far-field. Such a device is based on patterned surface directly written on van der Waals semiconductors; here α-MoO3. The resonances are found to strongly rely on in-plane hyperbolic polariton of patterned α-MoO3, exhibiting high quality factors up to 300, and to determine the characteristics of resultant tunable polarization and selection of the wavelength of reflection and transmission and regulation of output intensity. This is important to development of THz and LWIR miniaturized devices.