The present description relates to an olefin block copolymer preferably useful to form nonslip pads due to excellences in elasticity and heat resistance, and a sheet-shaped molded body comprising the olefin block copolymer The olefin block copolymer includes a plurality of blocks or segments, each of which includes an ethylene or propylene repeating unit and an α-olefin repeating unit at different weight fractions. The olefin block copolymer satisfies a defined relationship when a load of 5 to 10 kg is applied to a sheet-shaped molded body of the block copolymer for 12 hours or longer at a temperature of 60° C. or higher, and then removed.