Abstract: A portable screen assembly includes a casing having an opening extending in a longitudinal direction on the upper surface thereof and formed by a first and second case members that extend in the of longitudinal direction and are separable from each other, a spring-biased roll rotatably mounted to the casing, a screen wound around the spring-biased roll in storage and pulled out from the opening in use, a top bar fixed to one end of the screen and used also as a cover body to close the opening in storage, and an extendable column having one end erectably pivoted at a center part of the side face of the casing and, in an erected state, holding the pulled out screen in a stretched state. Thus, the portable screen assembly having reduced size and weight, capable of being easily handled and formed in a simple structure can be provided.