The effects of spin relaxation times of two-dimensional holes obtained from spin sensitive bleaching of intersubband absorption in p-type GaAs/AlGaAs quantum wells (QW) were investigated. The saturation of intersubband absorption of circularly polarized radiation was controlled by spin relaxation time of holes. The saturation behavior was determined for QW widths such that saturation intensity substantially decreased with narrowing of QWs. The results show that spin relaxation is due to the D'yakonov-Perel' mechanism governed by hole-hole scattering.