an optical head apparatus applicable to an optical disc apparatus comprises , a case body having an open surface and a window through which an opto - electronic component can be positioned and housing optical components inside it , a lid being attachable and detachable with respect to the open surface of the case body , and a flexible printed circuit board having a base portion which is adhered to the lid and on which electronic components are mounted and a protruding portion protruding from the base portion and having an opto - electronic component fixed to the distal end portion of it , the opto - electronic component being electrically connected with an electronic circuit which is formed by the electronic components , the distal end portion of the protruding portion of the flexible printed circuit board being fixed to the case body so that the opto - electronic component is position to the window .