  We present the results of 8 epochs of simultaneous UV and X-ray observations
of the highly variable ultraluminous X-ray source (ULX) Holmberg II X-1 with
AstroSat -- Indian multiwavelength space satellite. During the entire
observation period from late 2016 to early 2020, Holmberg II X-1 showed a
moderate X-ray luminosity of $8\times10^{39}$ erg/s and a hard power-law
spectrum with $\Gamma \lesssim 1.9$. Due to low variability of the object in
X-rays (by a factor 1.5) and insignificant variability in the UV range (upper
limit $\approx25$%) we could not find reliable correlation between flux changes
in these ranges. Inside each particular observation, the X-ray variability
amplitude is higher, it reaches a factor of 2-3 respect to the mean level at
the time scales of $\sim10$ ks or even shorter. We discussed our results in
terms of three models of a heated donor star, a heated disk and a heated wind,
and estimated the lower limit to the variability which would allow to reject at
least part of them.
