A dust collecting device, comprising: a body case having an airflow suction portion and an airflow discharge portion; a fan installed in the body case and configured to discharge an airflow sucked into the body case through the airflow suction portion to the outside of the body case through the airflow discharge portion; and a cyclonic separating unit configured to swirl, by the fan, the airflow sucked into the body case through the airflow suction portion and to separate dust contained in the sucked airflow, wherein the cyclonic separating unit includes: a cylinder having an airflow inlet disposed at a lower end side of the cylinder and an airflow outlet disposed at an upper end side of the cylinder; a swirling unit provided between the airflow inlet and the airflow outlet in the cylinder; a dust exhaust port provided in a circumferential wall of the cylinder between the swirling unit and the airflow outlet; and a mesh filter having such a configuration that the cyclonic separating unit is configured to exhaust the dust to the dust exhaust port by moving the dust along a slant surface of the mesh filter, wherein the mesh filter is provided between the swirling unit and the airflow outlet in the cylinder, and the mesh filter includes: a reticulated cylinder body having an airflow-outlet-side opening connected to the airflow outlet, a swirling-unit-side opening directed to the swirling unit, and a reticulated cover configured to cover the swirling-unit-side opening, wherein the reticulated cover includes a protrusion portion axially protruding toward the swirling unit at the center thereof and has such a shape that the reticulated cover is gradually inclined from the protrusion portion toward the airflow outlet up to an outer peripheral portion thereof. a body case having an airflow suction portion and an airflow discharge portion; a fan installed in the body case and configured to discharge an airflow sucked into the body case through the airflow suction portion to the outside of the body case through the airflow discharge portion; and a cyclonic separating unit configured to swirl, by the fan, the airflow sucked into the body case through the airflow suction portion and to separate dust contained in the sucked airflow, wherein the cyclonic separating unit includes: a cylinder having an airflow inlet disposed at a lower end side of the cylinder and an airflow outlet disposed at an upper end side of the cylinder; a swirling unit provided between the airflow inlet and the airflow outlet in the cylinder; a dust exhaust port provided in a circumferential wall of the cylinder between the swirling unit and the airflow outlet; and a mesh filter having such a configuration that the cyclonic separating unit is configured to exhaust the dust to the dust exhaust port by moving the dust along a slant surface of the mesh filter, wherein the mesh filter is provided between the swirling unit and the airflow outlet in the cylinder, and the mesh filter includes: a reticulated cylinder body having an airflow-outlet-side opening connected to the airflow outlet, a swirling-unit-side opening directed to the swirling unit, and a reticulated cover configured to cover the swirling-unit-side opening, wherein the reticulated cover includes a protrusion portion axially protruding toward the swirling unit at the center thereof and has such a shape that the reticulated cover is gradually inclined from the protrusion portion toward the airflow outlet up to an outer peripheral portion thereof. a cylinder having an airflow inlet disposed at a lower end side of the cylinder and an airflow outlet disposed at an upper end side of the cylinder; a swirling unit provided between the airflow inlet and the airflow outlet in the cylinder; a dust exhaust port provided in a circumferential wall of the cylinder between the swirling unit and the airflow outlet; and a mesh filter having such a configuration that the cyclonic separating unit is configured to exhaust the dust to the dust exhaust port by moving the dust along a slant surface of the mesh filter, wherein the mesh filter is provided between the swirling unit and the airflow outlet in the cylinder, and the mesh filter includes: a reticulated cylinder body having an airflow-outlet-side opening connected to the airflow outlet, a swirling-unit-side opening directed to the swirling unit, and a reticulated cover configured to cover the swirling-unit-side opening, wherein the reticulated cover includes a protrusion portion axially protruding toward the swirling unit at the center thereof and has such a shape that the reticulated cover is gradually inclined from the protrusion portion toward the airflow outlet up to an outer peripheral portion thereof. a reticulated cylinder body having an airflow-outlet-side opening connected to the airflow outlet, a swirling-unit-side opening directed to the swirling unit, and a reticulated cover configured to cover the swirling-unit-side opening, wherein the reticulated cover includes a protrusion portion axially protruding toward the swirling unit at the center thereof and has such a shape that the reticulated cover is gradually inclined from the protrusion portion toward the airflow outlet up to an outer peripheral portion thereof.