To provide a foam that generates a minus ion continuously and is useful for relaxation.

This polyolefin foam comprises a resin composition layer, on at least one part of a surface thereof, that contains a polymeric compound hard to be charged with static electricity, a mineral containing a rate element and at least one of either tormarine or far-infrared radiating ceramic, and discharges the minus ion and at the same time radiates far-infrared. Effect of this invention is remarkable when it is applied to an electrically conductive crosslinked polyethylene foam.