Abstract: In a portable auxiliary device for making stereoscopic image, a first rotatable assembly and a second rotatable assembly are rotatably mounted on an operation platform, and further respectively mounted with a first image catching device and a second image catching device thereon; a first optical guiding member and a second optical guiding member are respectively connected to the first rotatable assembly and the second rotatable assembly, and further respectively projects a first guiding light beam and a second guiding light beam. When the first rotatable assembly and the second rotatable assembly is operated to make the first guiding light beam and the second guiding light beam converged in a guided convergent position, a first optical axis of the first image catching device and a second optical axis of the second image catching device are simultaneously aligned to converge in a set convergent position.