The present invention relates to a resin foam including a foam layer and a surface layer, in which the foam layer has a same composition as the surface layer, and the surface layer has a surface coating ratio defined by the following formula (1) of 40% or more: Surface   Coating   Ratio  ( % ) = [ ( Area   of   surface ) - ( Area   of   pores   existing   in   surface ) ] ( Area   of   surface ) × 100 ( 1 )