A device for filtering ballast water which performs filtering by installing a filter element having a conical shape in a concentric circle direction inside the device for filtering ballast water that accommodates a filter portion, and introducing ballast water from a lower end of the device for filtering and passing same through the filter element inside the device for filtering, and for discharging backwash water containing foreign substances that are inside a filter by ways of differential pressure, which is created by a driving portion communicating with a filter element by rotating an aspiration portion that is located on the lower end of the device for filtering. In particular, the present invention relates to a candle-type device for filtering ballast water, wherein the driving portion is positioned on a lower portion of the housing so that more filter elements can be accommodated inside the housing.