The present invention relates to an expanding structure for a bench. According to an embodiment of the present invention, the expanding structure for a bench provides an expanded space on which a user can sit, by being formed in a landscape unit providing a plant cultivation space and a sitting space by ascending from a footpath inside or outside a building. The expanding structure for a bench includes: a sitting unit including a vertical surface erect from the footpath, a horizontal surface extended from the vertical surface to the plant cultivation space, and an extension surface extended downward from the horizontal surface to a planting unit providing the plant cultivation space； an extension unit moved from the sitting unit to the planting unit in a first direction by being unwound by a first outer force while being accommodated in a first accommodation space dented from the extension surface and wound in a second direction which is an opposite direction of the first direction when the first outer force is released； and a hanging unit moved to a second position in which the hanging unit protrudes to the upper side of the planting unit, by rotating in a first position hidden in the planting unit by a second outer force. The extension unit includes: a first fixing unit fixed to the first accommodation space and having a rotation shaft； a rotation unit rotating around the rotation shaft； and a bench unit wound on the outer surface of the rotation unit. The bench unit is coupled to the hanging unit at the second position while moving in the first direction. So, the bench unit can be unfolded from the sitting unit to the hanging unit.본 발명의 일 실시예에 따른 벤치 확장 구조는, 건축구조물의 실내 또는 실외에서, 보행로로부터 상승되어 식물재배공간 및 착석공간을 제공하는 조경부에 형성되어 사용자가 착석할 수 있는 확장된 공간을 제공하는 벤치 확장 구조에 있어서, 상기 보행로로부터 기립된 수직면, 상기 수직면으로부터 상기 식물재배공간으로 연장된 수평면 및 상기 수평면으로부터 상기 식물재배공간을 제공하는 식재부를 향해 하향 연장된 연장면을 구비하는 착석부, 상기 연장면으로부터 함입된 제1 수용공간에 수용된 채, 제1 외력에 의해 권출되어 상기 착석부로부터 상기 식재부를 향한 제1 방향으로 위치 이동되며, 상기 제1 외력이 해제되면
