We show that two g-wave components of the order parameter are induced
by the internal orbital motion of d-wave pairing electrons in the pres
ence of a magnetic field without assuming additional pairing interacti
ons. Near a d-wave vortex center, the g-wave components with a relativ
e phase pi/2 have an opposite winding number with respect to the domin
ant d-wave component. The spatial dependence of the magnetically induc
ed g-wave components is the same as that of; an induced s-wave compone
nt by spatial variation of the d-wave component and each g-wave compon
ent has a fourfold symmetry. Therefore, the vortex has an eight-lobe p
rofile.