A flow rate control valve and a method for injecting a fluid into an underground formation are provided. 3 \u03bcm or more and below 20 \u03bcm which is equivalent to or smaller than that of its matrix, and a porosity of 60% or more and below 95% which is higher than that of the matrix; and having the other specified relations. The method of fabricating the conditioning disk is performed by forming adhesive films for attaching the abrasive grains onto the body surface multiple times. A portion of the liquid composition is diluted with the solvent forming a use solution with a third predetermined viscosity; where the third predetermined viscosity is greater than the second viscosity.