An apparatus for producing a microporous plastic film comprising a pattern roll having large numbers of high-hardness, fine particles; an anvil roll opposing the pattern roll; a conveying means for passing a plastic film through a gap of both rolls; a stationary frame rotatably supporting one of both rolls; a pair of laterally arranged movable frames rotatably supporting the other roll; and a pair of laterally arranged carriages to each of which each of the movable frames is fixed; at least one of the carriages moving in a running direction of the plastic film to generate positional difference between a pair of the movable frames, so that the center axes of both rolls are relatively inclined to each other.