PURPOSE: To wash a filter without wasting time and labor by engaging the back surface of a filter with a filter fixture to hang the filter and immersing it in a solvent to move it by a driving means.

CONSTITUTION: A filter fixture 24 is installed in a washing tank 3 storing a solvent 2. The back surface of a filter 1 is engaged with the filter fixture 24 to hang the filter 1 with the opening of its upper surface being directed downward. The filter 1 is immersed in the solvent 2. The filter fixture 24 is moved in the washing tank 24 by a driving means 4, and the filter 1 is vertically oscillated or rotated in the solvent 2. In this way, the filter is washed with larger washing force than that of washing with hand.