Provided is a forming apparatus which forms the upper surface of an adhesive substance in the shape of ribs so as to prevent or reduce a wavy surface or unintended inclination thereof, the adhesive substance being adapted to adhere tiles to a laying surface. The forming apparatus comprises a tongue forming means, the tongue forming means having a plurality of tongues and a tongue securing portion; a grasping means; and a contact means. The plurality of tongues have a gap therebetween, and a free end or a tip end protruded from a base end which is located on a bottom defining line in the direction of the protrusion perpendicular to the bottom defining line that is located on a tongue existence plane. The tongue securing portion allows the base end of the plurality of tongues to be attached to an edge portion along the bottom defining line to secure the base end of the plurality of tongues along the bottom defining line. The grasping means is gripped by a hand of a user and attached directly or indirectly to the tongue securing portion. The contact means has at least two contact points which contact at least two points on an imaginary plane perpendicular to the direction of the protrusion and is directly or indirectly attached to the tongue forming means, wherein the at least two contact points or legs thereof perpendicular to the tongue existence plane exist generally on a contact defining line or a line segment which is present on the tongue existence plane away from the bottom defining line in the direction of the protrusion.
