PROBLEM TO BE SOLVED: To provide a slimicide for a piping with traps and a slime control method using the same.SOLUTION: As a slimicide is used a composition comprising a non-bleaching powder-based antibacterial agent (A component) for controlling slime, a bicarbonate or/and a carbonate (B component) for quickly dissolving a tablet, an organic acid (C component), HPC (D component) for controlling breakdown of the tablet. By doing so, the antibacterial agent can be released uniformly over 1 to 10 hours. Thus, the slime in the piping can be removed and prevented without clogging the piping having traps.