  We present a detailed multi-frequency analysis of an intense monitoring
programme of Seyfert 1 galaxy NGC 4593 over a duration of nearly for a month
with Swift observatory. We used 185 pointings to study the variability in six
ultraviolet/optical and two soft (0.3-1.5 keV) and hard X-ray (1.5-10 keV)
bands. The amplitude of the observed variability is found to decrease from high
energy to low energy (X-ray to optical) bands. Count-count plots of
ultraviolet/optical bands with hard X-rays clearly suggest the presence of a
mixture of two major components: (i) highly variable component such as hard
X-ray emission and (ii) slowly varying disc-like component. The variations
observed in the ultraviolet/optical emission are strongly correlated with the
hard X-ray band. Cross-correlation analysis provides the lags for the longer
wavelengths compared to the hard X-rays. Such lags clearly suggest that the
changes in the ultraviolet/optical bands follow the variations in the hard
X-ray band. This implies the observed variation in longer wavelengths is due to
X-ray reprocessing. Though, the measured lag spectrum (lag vs. wavelength) is
well described by {\lambda}^(4/3) as expected from the standard disc model, the
observed lags are found to be longer than the predicted values from standard
disc model. This implies that the actual size of the disc of NGC 4593 is larger
than the estimated size of standard thin disc as reported in AGN such as NGC
5548, Fairall 9.
