A polysiloxane having a siloxane structure of the following formulas (1) and (2): ##STR1## wherein, R.sup.1 is a C.sub.1 to C.sub.6 alkyl group or C.sub.1 to C.sub.21 acyl group, a is 1 to 200, b is 1 to 200, t is 2 or 3 and r is 1 to 100, and a rubber composition containing the same.

A rotary head drum apparatus includes a stator drum. A rotary drum is provided with a plurality of magnetic heads and rotates the magnetic heads. The rotary drum is mounted for rotational movement with respect to the stator drum. A rotary transformer includes a stator-side rotary transformer provided on the stator drum and a rotating-side rotary transformer fixed to the rotary drum. The stator-side rotary transformer and the rotating-side rotary transformer are adapted to send and receive signals to each other. An adhesive providing gap is disposed between the rotating-side rotary transformer and the rotary drum for receiving an adhesive for bonding the rotating-side rotary transformer to the rotary drum. An adhesive splashing prevention part is provided on the rotating-side rotary transformer and receives adhesive splashing from the adhesive providing gap. The adhesive splashing prevention part includes a first ring member having an opening in the center thereof and bonded to the rotating-side rotary transformer with a thermosetting resin adhesive. A second ring member is bonded to the first ring member with the thermosetting resin adhesive and has in the center thereof an opening whose diameter is smaller than the diameter of the opening of the first ring member. The adhesive splashing prevention part forms a space receiving adhesive splashing from the adhesive providing part.