The object of the present invention is to provide a means for utilizing cells that have effects on wound healing as wound-healing promoting materials by efficiently concentrating such cells within a short period of time. The present invention provides a wound-healing promoting material which comprises a sheet-like porous body having on its surface at least leukocytes and/or platelets, a method for producing the same, a device for producing the same, and a method for treating wound sites using the same.