Upon using a stethoscope, there is a problem that it had been needed to interrupt work and mount the stethoscope using both hands, resulting in poor work efficiency. Also, when it is needed to repeatedly mount and unmount the stethoscope for such as a group examination, for example, it had been necessary to continuously carry out an operation of expanding ear tubes many times, which is complicated. Thus the present invention provides an attachment for a stethoscope comprising a mounting part which can be mounted to both of ear tubes, and a manipulating part for manipulating the mounting part, the manipulating part and the mounting part being connected through a rotatable fulcrum, so that the mounting part may be opened and closed by opening and closing operation of the manipulating part.