DsTau is an experiment at the CERN SPS, approved by CERN in June 2019 as NA65, to study $\nu_\tau$ production aiming at providing important data for future $\nu_\tau$ studies. A precise measurement of the $\nu_\tau$ cross section would enable a search for new physics effects in $\nu_\tau$ CC interactions. It also has practical importance for the next generation experiments for neutrino oscillation studies and astrophysical $\nu_\tau$ observations. The practical way of producing a $\nu_\tau$ beam is by the sequential decay of $D_s$ mesons produced in high-energy proton interactions. However, there is no experimental measurement of the $D_s$ differential production cross section in fixed target experiments using proton beams, which leads to a large systematic uncertainty on the $\nu_\tau$ flux estimation. The DsTau experiment aims to reduce the systematic uncertainty in the current $\nu_\tau$ cross section measurement to 10% or below, by measuring the $D_s$ differential production cross section (especially longitudinal dependence). For this purpose, emulsion detectors with a spatial resolution of 50 nm will be used allowing the detection of $D_s \rightarrow \tau \rightarrow X$ double kinks in a few mm range. During the physics runs, 2.3$\times$10$^8$ proton interactions will be collected in the tungsten target, and 1000 $D_s \rightarrow \tau$ decays will be detected. In addition to the primary aim, the analysis of $\mathcal{O}(10^5)$ charmed particle pairs can provide valuable by-products such as studies of the forward charm production and the intrinsic charm content in proton. Results from the test runs and the pilot run will be presented together with a prospect for the physics runs in 2021 and 2022.