Abstract: A support body is provided defining a first pair of sides, a circular recess in the body opening outwardly of the first pair of sides and a second pair of sides for abutting against a surface whose orientation relative to the horizontal is to be measured. A level element is adjustably, rotatably disposed in the recess and defines a hollow housing having opposite sides including at least one outer side facing outwardly of the recess. The opposite sides include central journal bearing structures and the opposite ends of a support shaft are journaled from the journal bearing structures. A weighted pendulum-type upstanding pointer arm has a midportion thereof supported from the shaft and includes an upper end indicator or portion swingable in close proximity to the inner surface of the outer periphery of the outer side of the housing, the outer periphery being constructed of transparent material and provided with peripherally spaced indicia.