The cosmic microwave background ( CMB ) has non-Gaussian features in the temperature fluctuations .
An anomalous cold spot surrounded with a hot ring , called the Cold Spot is one of such features .
If a large underdence region ( supervoid ) resides towards the Cold Spot , we would be able to detect a systematic shape distortion in the images of background source galaxies via weak lensing effect .
In order to estimate the detectability of such signals , we used the data of N -body simulations to simulate full-sky ray-tracing of source galaxies .
We searched for a most prominent underdense region using the simulated convergence maps smoothed at a scale of 20 degree and obtained tangential shears around it .
The lensing signal expected in a concordant \Lambda CDM model can be detected at a signal-to-noise ratio S / N \sim 3 .
If a supervoid with a radius of \sim 200 h ^ { -1 } \textrm { Mpc } and a density contrast \delta _ { 0 } \sim - 0.3 at the centre resides at a redshift z \sim 0.2 , on-going and near-future weak gravitational lensing surveys would detect a lensing signal with S / N \gtrsim 4 without resorting to stacking .
From the tangential shear profile , we can obtain a constraint on the projected mass distribution of the supervoid .