PURPOSE: To provide a non-angular slit filter capable of being easily attached to an existing pipeline or machinery.

CONSTITUTION: This non-angular slit filter is constituted by engaging a large number of linear wire materials 1 for a filter each having at least a flat top surface P and a definite cross-sectional shape with a large number of linear cut grooves parallelly provided to a non-angular plate member 3 having a large number of through-holes 4 bored therein through the engaging protruding pieces 2 provided to the lower part of the wire materials to fix them to the plate member 3 and forming a large number of linear filtering slits 6 between the adjacent wire materials 1.