Embodiments of the present invention may provide a cradle transferring device, which moves and withdraws a cradle to and from an examination table of an MRI apparatus in a PET-MRI hybrid system. The cradle transferring device includes: a cradle, on which a subject lies; a shuttle table supporting the cradle and moving and withdrawing the cradle to and from the examination table of the MRI apparatus; and a cradle receiving member provided on the examination table of the MRI apparatus. The shuttle table is provided with a transfer member for holding and transferring the cradle and a transfer member driving means for reciprocating the transfer member along the shuttle table. The cradle transferring device is further provided with a cradle locking means, which locks the cradle to the examination table after the cradle is moved to the examination table. The cradle transferring device moves the cradle to the examination table of the MRI apparatus and accurately withdraws the cradle from the examination table of the MRI apparatus after the examination in the MRI apparatus.