PROBLEM TO BE SOLVED: To provide a dust collecting device having a simple structure, convenient to use, and suitable for a self-propelled vacuum cleaner.SOLUTION: The dust collecting device includes: a dust collecting container for storing dust; an inflow passage for making dust sucked from a suction hole at the bottom of the self-propelled vacuum cleaner flow in the dust collecting container together with air; and a filter portion for passing the air flowing into the dust collecting container therethrough and catching the dust. The dust collecting container has a bottom portion, a side wall portion rising up from the peripheral edge of the bottom portion, and an opening having a periphery defined by the side wall portion. The inflow passage has an inflow passage front end removably connected to a suction passage communicating with a suction hole, and an inflow passage base end connected to a side wall portion of the dust collecting container and forming a dust inflow hole, wherein the inflow passage is incli
