A draining anti-siphon device and a washing machine provided with same. Provided is a draining anti-siphon device (8), comprising a water outlet pipe and an air pipe (17), wherein the water outlet pipe comprises a first water pipe (16) and a second water pipe (15) which are connected with each other, the pipe diameter of at least part of the second water pipe (15) is larger than the pipe diameter of the first water pipe (16), one end of the air pipe (17) is communicated with the second water pipe (15), and the communicating position of the air pipe (17) and the second water pipe (15) is located at a radial surface of the second water pipe (15), so that siphon reverse flow is prevented by means of a diameter changing structure of the air pipe (17) and the water outlet pipe; by means of the structure, the water pressure at the air pipe (17) is small, which effectively prevents dirty water flowing back to a washing outer drum (2) through the air pipe (17) due to water pressure during drainage. According to a was
