A milking device whose portion corresponding particularly to a deforming memberis easily cleaned so that it can be cleanly used. The milking device has a receivingcontainer (11), a milking device body (21) having an installation/removal section(25), a negative pressure generation member (30) installed on the milking devicebody, and an operation means for the negative pressure generation member (30).The milking device body has a milking diameter-expanded section (22), a smallvalve chamber (26), and an installation section (41) communicating with thesmall valve chamber and to which the negative pressure generation member forgenerating negative pressure for milking is installed. The negative pressuregeneration member has a coupling section (35) coupled to the operation means,an installation/removal section (53) formed of an elastic, relatively softmaterial and installed on and removed from the installation section, a wall section(31) having a rigidity sufficient to hold its outer shape, and a deformation section(32) integrally provided inside the wall section and having less wall thicknessthan the wall section so that the deformation section is deformed under forcefrom the coupling section to generate the negative pressure.
