A foam, wherein proportion of a hard component at 30°C is 50% or less relative to all components and a proportion of a middle component at 160°C is 65% or less relative to all components, in a technique to determine proportions of three components, hard, middle and soft components by pulsed NMR, measured according to the method in the description, wherein a free induction decay curve due to 1H spin-spin relaxation is obtained by pulsed NMR measurement and waveforms of the free induction decay curve can be separated into three curves derived from three components, hard, middle, and soft components, sequentially, from the shorter relaxation time, wherein the foam is obtained by crosslinking and foaming a foamable composition comprising: a polyolefin-based resin having an endothermic peak, as measured by a differential scanning calorimeter, present at 160°C or higher and a melt flow rate at 230°C of 2.0 to 20 g/10 minutes in an amount of 10 to 30 mass% relative to the total amount of resin components in the foamable composition; a polyolefin-based resin having an endothermic peak, as measured by a differential scanning calorimeter, present at 130 to 150°C and a melt flow rate at 230°C of 0.4 to 2.0 g/10 minutes in an amount of 30 to 50 mass% relative to the total amount of resin components in the foamable composition; and a polyolefin-based resin having an endothermic peak, as measured by a differential scanning calorimeter, present at 110 to 150°C and a melt flow rate at 190°C of 2.5 to 20 g/10 minutes in an amount of 30 to 50 mass% relative to the total amount of resin components in the foamable composition, and wherein the melt flow rate is measured according to JIS K 7210, measured at a load of 2.16 kgf. wherein a free induction decay curve due to 1H spin-spin relaxation is obtained by pulsed NMR measurement and waveforms of the free induction decay curve can be separated into three curves derived from three components, hard, middle, and soft components, sequentially, from the shorter relaxation time, wherein the foam is obtained by crosslinking and foaming a foamable composition comprising: a polyolefin-based resin having an endothermic peak, as measured by a differential scanning calorimeter, present at 160°C or higher and a melt flow rate at 230°C of 2.0 to 20 g/10 minutes in an amount of 10 to 30 mass% relative to the total amount of resin components in the foamable composition; a polyolefin-based resin having an endothermic peak, as measured by a differential scanning calorimeter, present at 130 to 150°C and a melt flow rate at 230°C of 0.4 to 2.0 g/10 minutes in an amount of 30 to 50 mass% relative to the total amount of resin components in the foamable composition; and a polyolefin-based resin having an endothermic peak, as measured by a differential scanning calorimeter, present at 110 to 150°C and a melt flow rate at 190°C of 2.5 to 20 g/10 minutes in an amount of 30 to 50 mass% relative to the total amount of resin components in the foamable composition, and wherein the melt flow rate is measured according to JIS K 7210, measured at a load of 2.16 kgf. a polyolefin-based resin having an endothermic peak, as measured by a differential scanning calorimeter, present at 160°C or higher and a melt flow rate at 230°C of 2.0 to 20 g/10 minutes in an amount of 10 to 30 mass% relative to the total amount of resin components in the foamable composition; a polyolefin-based resin having an endothermic peak, as measured by a differential scanning calorimeter, present at 130 to 150°C and a melt flow rate at 230°C of 0.4 to 2.0 g/10 minutes in an amount of 30 to 50 mass% relative to the total amount of resin components in the foamable composition; and a polyolefin-based resin having an endothermic peak, as measured by a differential scanning calorimeter, present at 110 to 150°C and a melt flow rate at 190°C of 2.5 to 20 g/10 minutes in an amount of 30 to 50 mass% relative to the total amount of resin components in the foamable composition, and wherein the melt flow rate is measured according to JIS K 7210, measured at a load of 2.16 kgf.