Abstract: A device for opening envelopes includes a movable knife blade which is mounted on a swingable knife holder and is urged towards a complementary edge which is preferably formed by a further knife blade. The movable knife blade is inclined in its longitudinal direction. A cutting operation is effected at the point of engagement of the movable knife blade with the stationary one. Movement of the movable knife blade causes the edge of an envelope be gradually severed. The knife blades are supported on a base part which preferably has, underneath the cutting parts, a removable waste drawer.