  We report on efficient spin current generation at room temperature in rutile
type WO$_{2}$ grown on Al$_{2}$O$_{3}$(0001) substrate. The optimal WO$_{2}$
film has (010)-oriented monoclinically distorted rutile structure with metallic
conductivity due to 5$\it{d}$$^2$ electrons, as characterized by x-ray
diffraction, electronic transport, and x-ray photoelectron spectroscopy. By
conducting harmonic Hall measurement in Ni$_{81}$Fe$_{19}$/WO$_{2}$ bilayer, we
estimate two symmetries of the spin-orbit torque (SOT), i.e., dampinglike (DL)
and fieldlike ones to find that the former is larger than the latter. By
comparison with the Ni$_{81}$Fe$_{19}$/W control sample, the observed DL SOT
efficiency $\xi$$_{DL}$ of WO$_{2}$ (+0.174) is about two thirds of that of W
(-0.281) in magnitude, with a striking difference in their signs. The magnitude
of the $\xi$$_{DL}$ of WO$_{2}$ exhibits comparable value to those of widely
reported Pt and Ta, and Ir oxide IrO$_{2}$. The positive sign of the
$\xi$$_{DL}$ of WO$_{2}$ can be explained by the preceding theoretical study
based on the 4$\it{d}$ oxides. These results highlight that the epitaxial
WO$_{2}$ offers a great opportunity of rutile oxides with spintronic
functionalities, leading to future spin-orbit torque-controlled devices.
