  The bulge of M31 is of interest in the context of the nature of galactic
bulges and how their structure relates to bulge formation mechanisms and their
subsequent evolution. With the UVIT instrument on AstroSat, we have observed
the bulge of M31 in five far ultraviolet (FUV) and near ultraviolet (NUV)
filters at 1" spatial resolution. Models for the luminosity distribution of the
bulge are constructed using the UVIT data and the galaxy image-fitting
algorithm GALFIT. We fit the bulge without nuclear region with a Sersic
function the five images and find Sersic indices ($\simeq2.1$ to 2.5) similar
to previous studies but smaller $R_e$ values ($\simeq0.5$ to 0.6 kpc). When the
images include the nuclear region, a multicomponent model is used to find the
best-fit. We use an 8-component fit for the FUV 148nm image, which has the
highest sensitivity. The other images (169 to 279 nm) are fit with 4-component
models. The dust lanes in the bulge region are recovered in the residual image
after subtraction of the bright bulge light using the multicomponent model. The
dust lanes show that M31's nuclear spiral is visible in absorption at NUV and
FUV wavelengths. The bulge images show boxy contours in all five UVIT
wavebands, which is confirmed by fitting using GALFIT. The Sersic indices of
$\sim$2.1-2.5 are intermediate between expected values for a classical bulge
and for a pseudobulge. The boxiness of the bulge provides further evidence that
M31's bulge has contributions from a classical bulge and a pseudobulge.
