We investigated the structure of convective flows in the solar photosphere on subgranulation scales by solving the nonequilibrium inverse radiative transfer problem with the use of profiles of the neutral iron line λ ≈ 523.4 nm. Acoustic and gravity waves were removed by k-ω filtration. An asymmetrical character of the distribution of the line of sight velocity takes place inside large convective flows (sizes are about 1.5" and more) in the low photosphere and bottom of the middle photosphere. In the higher layers of the photosphere the asymmetry of large convective flows is weaker. For small structures (sizes less than 1.5") the distribution is more symmetrical along all the heights. The asymmetry for the temperature distribution is less expressed. We revealed thin structure of convective flows: large flows consist of two (or more?) smaller ones. The observed asymmetry of the velocity distribution in convective structures is due to thin structure of convective flows, on the one hand, and the spatial smearing, on the other hand.