To shorten the axial dimension so as to make a unit compact without affecting the unit lifetime (rolling lifetime).

A first thrust needle bearing 61 is sandwiched between a second housing 2 and a guide roller 37a, and a second thrust needle bearing 62 is sandwiched between a connecting plate 14 (a third housing) and the guide roller 37a. Recess parts 63, 64 to store the first and second thrust needle bearings 61, 62 are formed in both sides of the guide roller 37a, in which the first and the second thrust needle bearings 61, 62 contact.