invention and fig5 is an enlarged view of part p of fig4 in addition fig6 is a plan view illustrating the dynamic pressure generating groove of the fluid bearing apparatus according to another embodiment of the present invention each of the dynamic pressure generating grooves 150a according to the present invention is etched at a predetermined depth by an etching process when etching the plain surface there are two wall sides and one base side out of the two wall sides one is defined as a first side wall 150b and the other is defined as a second side wall 150c in order to define clearly the position and shape of the first and second side walls 150b and 150c a detailed explanation follows the inner diameter of the thrust bearing 150 having a doughnut shape is defined as a and the outer diameter is defined as g the imaginary concentric circles b c d e and f are formed first an imaginary line from the center o of the thrust bearing 150 to the outer diameter g is defined as h after that a part where the imaginary concentric circle b and line h meet a part where the imaginary concentric circle d and line h meet and a part where the imaginary concentric circle f and line h meet are defined as c.