Abstract: A lock assembly includes a core rotatably received in a casing and the core has first passages each having a first pin received therein. The casing has a protrusion in which second passages are defined and located in alignment with the first passages. Each second passage has a second pin received therein and biased by a spring so as to push a lower end of each first pin extended in the key way in the core. The second pins are located at a boundary surface between the core and the casing. A piece is received in the first passage and located at the boundary surface. A key with serration has a magnetic member which attracts the piece to move toward the key so that the piece is moved and the core is rotated relative to the casing.