Foam and method for producing same

The purpose of the present invention is to provide a polyolefin resin foam that can be used suitably in architectural, electrical, electronic, vehicular, and other such fields as various types of sealing materials having heat resistance with no difference between front and rear on upper and lower surfaces that sandwich, in the thickness direction, a foam having exceptional flexibility, cushioning properties, and heat insulating properties despite having low thickness. In essence, this foam is characterized in that the surface hardness of the foam measured by a micro-rubber hardness meter is 30-70 degrees and the centerline average roughness Ra of a first surface portion on one thickness-direction side of the foam and a second surface portion on the other thickness-direction side is 5-20 [mu]m.