Binoculars provided with first and second objective lens barrels respectively having objective lenses at an end, first and second eyepiece lens barrels respectively having eyepiece lenses and adapted to slide respectively on the other end portions of the first and second objective lens barrels, prisms positioned between the objective lenses and the eyepiece lenses and provided respectively in the first and second objective lens barrels, and a focusing mechanism provided with a focusing member and adapted to displace the first and second eyepiece lens barrels in the axial direction by the rotation of the focusing member, wherein each of the prisms is composed of a roof prism having an entrance face for receiving the light beam from the objective lens and an exit face for introducing the received light beam to the eyepiece lens, the exit face being so formed as to be loosely insertable in the eyepiece lens barrel and the periphery of the entrance face being fixed in the objective lens barrel so as that the exit face can enter the eyepiece lens barrel when the eyepiece lens barrel is auxiliary displaced toward the roof prism by the focusing mechanism.