A wire guide housing (1) which contains a wire guide (6) for supporting a running wire electrode (W) and in which a wire running passage (32, 23b, 41, 26, 63, 66a) through which the wire electrode passes is formed. The wire guide housing includes: a cleaning liquid supply opening (43), for introducing a cleaning liquid (C) into the wire guide housing; a cleaning liquid discharge opening (44), for discharging the cleaning liquid from the wire guide housing; a first flow passage (46), for connecting the cleaning liquid supply opening to the wire running passage; and a second flow passage (48), for connecting the wire running passage to the cleaning liquid discharge opening. The cleaning liquid flows into the wire running passage at a side more upstream than the wire guide.