PURPOSE: To provide a holding structure in which any number of platelike members such as circuit boards of the same shape can be fixedly held, which has a small number of components with less assembly labor and in which the members can be fixed without rattling and without movement.

CONSTITUTION: A plurality of holding protrusions 17 are formed on both end faces 16a of a circuit board 15 in one direction, and insertion holes 25 to be engaged with the protrusions 17 are opened at a sidewall 21 for holding the board 15 at a holder 20 corresponding to the protrusions 17. And, the protrusions 17 are respectively engaged with the holes 25, and the holder 20 having first and second holders 20a, 20b is assembled. In this case, at least any one of the faces 16a is elastically held by the one sidewall 21 of the holder 20, and the other face is pressed to the other sidewall of a holder 30 to be fixed.