The present invention relates to a high carbon steel sheet having chemical composition specified by JIS G 4051 (Carbon steels for machine structural use), JIS G 4401 (Carbon tool steels) or JIS G 4802 (Cold-rolled steel strips for springs), wherein the ratio of number of carbides having a diameter of 0.6 &mgr;m or less with respect to all the carbides is 80% or more, more than 50 carbides having a diameter of 1.5 &mgr;m or larger exist in 2500 &mgr;m2 of observation field area of electron microscope, and the &Dgr;r is more than −0.15 to less than 0.15. The high carbon steel sheet of the invention is excellent in hardenability and toughness, and formable with a high dimensional precision.