Remaining formwork for decoration, and wall surface structure of concrete structure

A decorative remaining formwork formed by combining a plurality of single frame plates defined by 3 or more edges comprising one edge arranged horizontally and at least one inclined edge inclined with respect to the horizontal edge,

• arranging the single frame plates so as to form a predetermined gap in a joint-shape between respective edges of the single frame plates adjacent each other,
• having a back plate on a concrete casting surface, the back plate covering the predetermined gap in a longitudinal direction, and being fixed to the single frame plate to connect the single frame plates adjacent each other, and
• a cross-sectional shape in a width direction of the back plate being formed into a shape enlarged from a contact surface with respect to the single frame plate toward an opposed surface with respect to the contact surface;
• and
• comprising a base unit formed by a combination of two single frame plates forming a rectangle shape by arranging the inclined edges in parallel via the predetermined gap, and
• having a pattern expressed by continuously arranging the base units in a predetermined direction or by continuously arranging the base units of which the directions are reversed and rotated or reversed or rotated in a predetermined pattern.