An electrolytic processing device has an electrolytic tank which comprises separably coupled upper and lower units. The upper and lower units can be coupled to each other to form a single electrolytic tank when electrolytic processing is to be performed. On the other hand, the upper and lower units can be replaced with other units independently. This allows the electrolytic solution in the lower unit to be changed simply by replacing the lower unit with another unit with a different electrolytic solution, without the need for draining and washing the lower unit used previously.