  We report a possible dipole anisotropy on acceleration scale $g_{\dag}$ with
147 rotationally supported galaxies in local Universe. It is found that a
monopole and dipole correction for the radial acceleration relation can better
describe the SPARC data set. The monopole term is negligible but the dipole
magnitude is significant. It is also found that the dipole correction is mostly
induced by the anisotropy on the acceleration scale. The magnitude of
$\hat{g}_{\dag}$-dipole reaches up to $0.25\pm0.04$, and its direction is
aligned to $(l,b) = (171.30^{\circ}\pm7.18^{\circ},
-15.41^{\circ}\pm4.87^{\circ})$, which is very close to the maximum anisotropy
direction from the hemisphere comparison method. Furthermore, robust check
shows that the dipole anisotropy couldn't be reproduced by isotropic mock data
set. However, it is still premature to claim that the Universe is anisotropic
due to the small data samples and uncertainty in the current observations.

Cosmology and Nongalactic Astrophysics