A slide-type lock lever release mechanism includes a slidable member (40) with a second acting surface slidable on the first acting surface of the lock lever (20) by a predetermined stroke for flexing the lock lever away from the second lock engaging member (211) to thereby release the engagement between the first and second lock engaging members, wherein at least one of the first and second acting surfaces having at least two acting surface sections (42, 43) such that a first acting surface section (42) is slidable on the other one of the acting surfaces (23) in a first segment of the predetermined stroke and a second acting surface section (43) is slidable on the other one (23) in a second segment of the predetermined stroke to thereby provide smooth release of the lock engagement with a relatively short stroke of the slidable means.