A portable display terminal for survey assistance includes: a screen unit and a selection unit of the portable display terminal; a design information acquisition unit configured to acquire design information including an identifier of a design drawing, and a plan view, a longitudinal sectional view, and a transverse sectional view that are associated with the identifier; a design information summarization unit configured to generate summary drawings of the design drawing; a design information selection display unit configured to line up and display a plurality of combinations of the summary drawings in a selectable manner; and a screen display unit configured to display an image of at least one of the plan view, the longitudinal sectional view, or the transverse sectional view of the design drawing associated with the combination of the summary drawings selected by a selection unit on a screen unit of the portable display terminal.