Afforded are thinning shears optimal for cutting crosswise hair growing along the scalp, as well as crosswise hair disturbing the passing of a comb through hair bundles. The thinning shears, in thinning shears furnished with a comb blade and a bar blade for haircutting, are characterized in that the comb blade is longer than the bar blade, and the tip-edge of the comb blade is corner-rounding processed. Adopting this configuration makes it possible to set the tip-edge portion of the comb blade on a scalp and slide the comb blade heading in the direction that the hair grows, to efficiently thin out crosswise hair such as would disturb combing, without injuring the scalp.