A mode-switching cam follower is disclosed, wherein the follower includes a body, a cam contact movably coupled to the body, and a latch member movably coupled to the body. A first block is constructed by first memory cell units each having of memory cells, a second block is constructed by second memory cell units each having a plurality of memory cells, and the memory cell array is constructed by arranging the first blocks on both end portions thereof and arranging the second blocks on other portions thereof. The expander member is then deactivated while leaving the wall portions in the outwardly placed position and the expander member is removed from said airway.