To provide a molding device for molding the upper surface of an adhesion composition into a wavy shape, capable of preventing or reducing the generation of ripples or unintended inclination of the upper surface of the adhesion composition for bonding a laying surface where tiles are laid and the tiles.

The molding device includes: tongue part forming means 40 provided with a tongue part fixing part for which the base ends of a plurality of tongue parts 41 and 61 are attached to an edge part along a bottom stipulating line and which fixes the base ends of the plurality of tongue parts along the bottom stipulating line; holding means 15 held by a hand of a user and directly or indirectly attached to the tongue fixing parts 41 and 61; and abutting means which has at least two abutting points to be abutted to at least two points of an assumed surface vertical to a projecting direction, for which the feet of the perpendicular to a tongue present surface of the at least two abutting points or the at least two abutting points are roughly present on an abutting stipulating line which is a line segment present more on the projecting direction side than the bottom stipulating line on the tongue present surface, and which is attached directly or indirectly to the tongue part forming means 40.