To provide a treatment agent and treatment method for simply and quickly solidifying an aqueous waste liquid such as wastewater contaminated by stripping of floor wax.

In treating the aqueous waste liquid, the treating agent mixed to the waste liquid includes a polymer water-absorbing agent and a dispersing agent that is mixed with the polymer water-absorbing agent to disperse the same in the waste liquid and that contains at least one kind of main components. Additionally, it is a wood powder that is at least the one kind of the main components of the dispersing agent. By mixing the treatment agent with the aqueous waste liquid, they both are entirely solidified into an aggregate of granules with a mean size in the range of 0.2 to 10 mm.