The invention relates to a foldable balcony device. The foldable balcony device comprises a rectangular framework, a rectangular pedal, a rectangular baffle and side handrails. The bottom edge of the rectangular pedal is hinged to a bottom beam of the framework. The bottom edge of the rectangular baffle is hinged to the top edge of the pedal. One end of each side guardrail is hinged to the middle of a corresponding side beam of the framework, and the other end of each side guardrail is hinged to the top of a corresponding side edge of the baffle. The pedal can be switched between a first position and a second position. When the pedal is located in the first position, the framework is covered by the pedal and the baffle, and the side guardrails, the framework and the pedal are parallel. When the pedal rotates from the first position to the second position, the pedal rotates from the position where the framework is covered to the position where the pedal is perpendicular to the framework, the baffle is moved from the position where the framework is covered to the position where the baffle is parallel to the framework in a spaced mode, and the side guardrails rotate from the position where the side guardrails are parallel to the framework to the position where the side guardrails are perpendicular to the framework. The foldable balcony device can be deformed into a structure similar to a balcony when required, use space of a user is increased, and the comfort degree of the user is improved.