A support device and a foldable device. The foldable device comprises a bendable structure (102) and a support device (101). The bendable structure (102) comprises a bending portion (1021), and a first non-bending portion (1022) and a second non-bending portion (1023) respectively located on two sides of the bending portion (1021). The support device (101) comprises a first support (1011), a second support (1012), a rotating shaft support (1013), and at least one support component (1014). The first support (1011) is used to support the first non-bending portion (1022), and the second support (1012) is used to support the second non-bending portion (1023). Each support component (1014) is connected to the rotating shaft support (1013), and is further used to be connected to the bending portion (1021) to provide support. The support device (101) is used to support the entire bendable structure (102) to avoid swelling of the bending portion (1021) of the bendable structure (102), thereby ensuring the flatness of the bendable structure (102).