Аннотация:We present the variability study of the lowest-luminosity Seyfert 1 galaxy NGC 4395 based on the photometric monitoring campaigns in 2017 and 2018. Using 22 ground-based and space telescopes, we monitored NGC 4395 with a ∼5 minute cadence during a period of 10 days and obtained light curves in the UV, V, J, H, and K/Ks bands as well as the Hα narrow-band. The RMS variability is ∼0.13 mag on \emph{Swift}-UVM2 and V filter light curves, decreasing down to ∼0.01 mag on K filter. After correcting for continuum contribution to the Hα narrow-band, we measured the time lag of the Hα emission line with respect to the V-band continuum as 55+27−31 to 122+33−67 min. in 2017 and 49+15−14 to 83+13−14 min. in 2018, depending on the assumption on the continuum variability amplitude in the Hα narrow-band. We obtained no reliable measurements for the continuum-to-continuum lag between UV and V bands and among near-IR bands, due to the large flux uncertainty of UV observations and the limited time baseline. We determined the AGN monochromatic luminosity at 5100Å λLλ=(5.75±0.40)×1039ergs−1, after subtracting the contribution of the nuclear star cluster. While the optical luminosity of NGC 4395 is two orders of magnitude lower than that of other reverberation-mapped AGNs, NGC 4395 follows the size-luminosity relation, albeit with an offset of 0.48 dex (≥2.5σ) from the previous best-fit relation of Bentz et al. (2013).