A glass substrate for a semiconductor package includes a first principal surface, a second principal surface, at least one hollowed-out portion, and at least one through hole formed in a surrounding of the at least one hollowed-out portion, wherein in a section of the at least one hollowed-out portion taken in a direction perpendicular to the first principal surface, a minimum diameter of the at least one hollowed-out portion is smaller than an opening diameter of the at least one hollowed-out portion at each of the first principal surface and the second principal surface.