A component-equipped-holder mounting structure comprises an electric component, a holder holding the electric component, and a holder mounting portion. The electric component includes a housing and a terminal extending therefrom. The holder includes a holder body, a pair of holder arms extending therefrom and configured to position the housing therebetween, the holder arms holding the electric component displaceably such that the electric component is positioned in a longitudinal direction of a mating terminal to be connected to the electric component, and a locking portion protruding from the pair of holder arms and configured to be brought into locking engagement with the housing. The holder mounting portion includes an accommodating portion accommodating therein a mating terminal with the holder slidably inserted into the holder mounting portion.