A purpose of the present invention is to provide a water storage tank for a washing machine. The water storage tank for the washing machine can maintain a good use feeling, inhibit an occurrence probability of maintenance operation and simultaneously reduce water consumption effectively. The water storage tank (4) for the washing machine in the present invention includes: a tank body (41) configured in a housing (2) of the washing machine (1) and having a water flowing portion (45) which is internally formed into a tubular shape and constitutes a continuous flow path surface (47) and an external surface portion (44) that constitutes a flexible external surface (41a); a water injecting port (42) arranged at one end of the tank body (41) and configured to inject water, as washing drum drainage water, discharged from a washing drum to the tank body (41); and a water outtake port(43) arranged at another end of the tank body (41) and capable of recirculating the water injected into the tank body (41) into the wash
