Method of bleaching cellulose pulp

A method of bleaching cellulose pulp, characterized by bleaching an alkaline aqueous slurry of cellulose pulp with oxygen or peroxide in the presence of one or more compounds selected as a bleaching assistant from a compound (U) represented by general formula (1), a compound (V) represented by general formula (2) and a compound (W) represented by general formula (3):

• 7 R1—O—[(C2H4O)m/(AO)n]—H (1) R2—O—[(C2H4O)m/(AO)p]—(AO)q—H (2) (R3)t—X—[(C2H4O)m/(AO)p]—(AO)r—H (3)
• (where R1 stands for a branched alkyl group having 6 to 12 carbon atoms, m stands for an average added mol number of 4 to 15, a stands for a propylene, butylene or phenylethylene group, n stands for an average added mol number of 0 to 4, the addition shown in [] is in a random or block form, R2 stands for a linear or branched alkyl group having 6 to 12 carbon atoms, p stands for an average added mol number of 0 to 3.9, q stands for an average added mol number of 0.1 to 4, R3 stands for a hydrogen atom, a methyl or ethyl group, or a branched alkyl group having 3 to 12 carbon atoms, t stands for an integer of 1 to 5, X stands for a residual phenol group, and r stands for an average added mol number of from 0, exclusive, to 4, inclusive):