Provided is a snap-fitting device for a softbox, comprising: a casing, on which a supporting member (6), a snap-fitting member and a light passage hole (4) are formed. The light passage hole (4) is a cylindrical hole and a flash lamp cap fixing device is formed therein. The flash lamp cap fixing device comprises a supporting platform (8) and a pressing plate (7) opposite to the supporting platform (8) and having an adjustable position relative to the supporting platform (8). The snap-fitting device for a softbox enables an on-camera flash lamp to use both an on-camera flash lamp folded softbox and a strobe flash lamp softbox, reducing expenses for a user.
