An elevation device is provided for a monitoring camera, including a top retaining barrel fixed to the top end of a high suspending post and downward fit onto a retained member. The retained member has a bottom forming the wire box. A retained cylinder has an outer circumference forming spaced locking blocks. The top retaining barrel comprises a locking tube receiving therein a toothed crown locking collar that comprises oppositely set first and second toothed crowns between when the locking blocks are movable to alternately carry out locking and unlocking operation. The locking tube forms a guide block corresponding to an inclined circumferential surface of a cam, whereby when the retained cylinder is driven upward in any orientation to fit into the locking tube, the inclined circumferential surface is guided by the guide block to correct orientation of the retained cylinder with respect to retained cylinder.