Abstract: A building block laying level indicating device adapted for use with a building block of general rectangular configuration wherein the block has a top and a bottom, front and rear walls and end faces. The front and rear walls of the block are connected by webs spaced from each other to provide a plurality of holes extending from the top through the bottom. The device has a planar base with three support members mounted thereon which are adapted to rest on the top of the block. A level indicating means is mounted on the base for visually indicating the level condition of the block. A positioning member is affixed to the planar base and extends downwardly therefrom so as to maintain the level in operating position when placed on the building block.