Provided is a treatment liquid for a semiconductor wafer or the like used in a process for forming a semiconductor. Namely a treatment liquid containing (A) a hypochlorite ion, and (B) an alkylammonium salt expressed by the following Formula (1), or the like is provided. (In the Formula, “a” is an integer from 6 to 20; R1, R2, and R3 are independently, for example, an alkyl group with a carbon number from 1 to 20; and X− is, for example, a chloride ion.)