A portable screen device including a casing, an extendable screen, and an extendable screen supporting column which has one end pivotally supported at a center portion of a back surface of the casing. The column can be pivoted to an extended position for holding the screen in an extended state. The column includes a plurality tubular members which slide with respect to each other. A lowermost tubular member has a first column lock mechanism for engaging the lowermost tubular member with an adjacent, upper tubular member to maintain the column at a desired height. A column lock releasing mechanism including a pedal is provided for releasing the engagement between the lowermost tubular member and the upper tubular member.