To prevent a rotation in the case of the opening and closing of a cock cover by constituting a drain cock device so as to control the rotation in the horizontal plane of the shaft of the cock cover, and to prevent the pulling of a release by the revolution and the deterioration of cutoff performance as seen in conventional devices.

A cock cover 5 is constituted in an openable and closeable manner in the vertical direction through a release 6, and the shaft 51 of the cock cover 5 is slid and contacted to the inner circumference of a guide section 41 for an attachment 4 fixed onto a drain-inlet metal fitting 2 and moved vertically. A projecting section 51a is formed to the outer circumference of the shaft 51 of the cock cover 5, a recessed section 41a is formed to the inner circumference of the guide section 41, and a rotation in a horizontal plane in the case of the opening and closing of the cock cover 5 is controlled by an engagement between the projecting section 51a and the recessed section 41a at that time.