To provide both an apparatus for feeding cotton capable of keeping the amount of fed cotton nearly constant even by an unskilled person and a method for feeding the cotton.

This apparatus for feeding cotton is obtained by installing a pressure measuring means 18 at one optional site A of a cotton feeding duct 16 and measuring the static pressure at this site when passing a wind through the interior of the cotton feeding duct 16 with a fan device 17 and conveying a tuft of a raw cotton 13 from an opening head 10 of an automatic cotton feeding apparatus. When the amount of the cotton passing through the interior of the cotton feeding duct 16 is large, the static pressure at the site A is raised. When the amount of the cotton is small, the static pressure is lowered. Thereby, the static pressure for providing a desired amount of fed cotton is predetermined and a feed rate regulator 14 for regulating the amount of the tuft is controlled with a controller 19 so as to maintain the target static pressure. When the static pressure is measured at two sites for measuring and the differential pressure thereof is measured, more accurate control of the amount of the fed cotton can be carried out.