PURPOSE: To prevent invasion of cold air from outside when harmful worms in a dust collecting chamber are driven away by circulating hot air within a cleaner body.

CONSTITUTION: A sealing plate 11 is mounted on a suction mouth 5 to clog an end on the rearside of a terminal insertion hole 5c and another end on the rearside of a hook escape hole 5b of the suction mouth 5. When cleaning is finished by an electric cleaner M, a joint 7 is dismounted from the suction mouth 5 and a shutter 6 is closed. Next, an electromotive fan is driven to circulate air in a cleaner body through a fan housing chamber, an air passage, the suction mouth 5 and a dust collecting chamber in this order. Then by heat of the electromotive fan, the air in the cleaner body is heated little by little. The air in the dust collecting chamber finally rises up to a prescribed temperature, whereby harmful worms such as ticks die.