The purpose of the present disclosure is to provide a method for producing pulp fibres for saccharification from the pulp fibres of used sanitary items, said pulp fibres for saccharification having low lignin contents distributed within a narrow range, and enabling the production of pulp fibres for saccharification having superior saccharification properties. The production method according to the present disclosure is characterised by comprising the following: a step for supplying a mixed solution (51) containing pulp fibres and highly-absorbent polymers sourced from used sanitary items to a treatment tank (31) via a mixed-solution supply port (32); a step for supplying an ozone-containing gas (53) to a treatment solution (52) within the treatment tank (31) via an ozone-containing-gas supply port (43); a step for lifting the ozone-containing gas (53) whilst lowering the pulp fibres and highly-absorbent polymers within the treatment tank (31), thereby bringing the ozone-containing gas (53) into contact with the pulp fibres and highly-absorbent polymers, and forming pulp fibres for saccharification from the pulp fibres; and a step for discharging the treatment solution (52) via a treatment-solution discharge port (33). The method is further characterised in that the pulp fibres for saccharification have lignin contents of 0.1% or less.