A cable mounting structure includes: a clustered cable including at least two cables covered with an integration coat; a spacer configured to divide the at least two cables that are exposed by removing the integration coat at one end of the clustered cable into two groups and array the two groups of the cables along a upper surface and a lower surface of the spacer; a mounting board including a upper-side cable joint electrode to which a cable arrayed on the upper surface of the spacer is joined and a lower-side cable joint electrode to which a cable arrayed on the lower surface of the spacer is joined; and a resin seal in which a joint between the mounting board and the at least two cables and a mounting board side of the spacer is covered and sealed with a sealing resin.