A handheld cleaner, comprising: a dust cup assembly comprising: a cup casing; a device housing configured to have a tube shape and disposed in the cup casing, wherein an outer end face of the device housing at an axial side thereof abuts against or extends out of a partial inner surface of the cup casing, and a dust removal chamber is defined between an inner surface of the cup casing and an outer peripheral surface of the device housing and surrounds the device housing along a circumferential direction of the device housing; and a negative pressure device located within the device housing and configured to enable dusty air to enter the dust removal chamber for dust and air separation; a holding assembly mounted to the dust cup assembly and configured for handholding, wherein the cup casing comprises: a cup body configured to have a tube shape and having an axial open end; and a cup cover assembly configured to detachably cover the open end of the cup body, wherein the cup cover assembly comprises: an inner cover disposed on the open end of the cup body; an outer cover disposed on the open end of the cup body and covered over the inner cover; and an in-cover air passage member detachably disposed between the inner cover and the outer cover or integrally formed to an inner surface of the outer cover, in which a communicating chamber is defined between the in-cover air passage member and the inner cover, and the negative pressure device is configured to enable the airstream separated from the dust removal chamber to enter the device housing through the communicating chamber. a dust cup assembly comprising: a cup casing; a device housing configured to have a tube shape and disposed in the cup casing, wherein an outer end face of the device housing at an axial side thereof abuts against or extends out of a partial inner surface of the cup casing, and a dust removal chamber is defined between an inner surface of the cup casing and an outer peripheral surface of the device housing and surrounds the device housing along a circumferential direction of the device housing; and a negative pressure device located within the device housing and configured to enable dusty air to enter the dust removal chamber for dust and air separation; a cup casing; a device housing configured to have a tube shape and disposed in the cup casing, wherein an outer end face of the device housing at an axial side thereof abuts against or extends out of a partial inner surface of the cup casing, and a dust removal chamber is defined between an inner surface of the cup casing and an outer peripheral surface of the device housing and surrounds the device housing along a circumferential direction of the device housing; and a negative pressure device located within the device housing and configured to enable dusty air to enter the dust removal chamber for dust and air separation; a holding assembly mounted to the dust cup assembly and configured for handholding, wherein the cup casing comprises: a cup body configured to have a tube shape and having an axial open end; and a cup cover assembly configured to detachably cover the open end of the cup body, a cup body configured to have a tube shape and having an axial open end; and a cup cover assembly configured to detachably cover the open end of the cup body, wherein the cup cover assembly comprises: an inner cover disposed on the open end of the cup body; an outer cover disposed on the open end of the cup body and covered over the inner cover; and an in-cover air passage member detachably disposed between the inner cover and the outer cover or integrally formed to an inner surface of the outer cover, in which a communicating chamber is defined between the in-cover air passage member and the inner cover, and the negative pressure device is configured to enable the airstream separated from the dust removal chamber to enter the device housing through the communicating chamber. an inner cover disposed on the open end of the cup body; an outer cover disposed on the open end of the cup body and covered over the inner cover; and an in-cover air passage member detachably disposed between the inner cover and the outer cover or integrally formed to an inner surface of the outer cover, in which a communicating chamber is defined between the in-cover air passage member and the inner cover, and the negative pressure device is configured to enable the airstream separated from the dust removal chamber to enter the device housing through the communicating chamber.