In 1915, the plaintiff in this action obtained a decree of divorce from the defendant, which decree awarded her certain property and the custody of their daughter, a child then of the age of fifteen years, the decree being silent as to any provision made for the maintenance of the child. The decree of divorce was appealed from by the defendant, and the judgment of the lower court was affirmed by this court. This action was commenced by the plaintiff, who has, since the decree of divorce, borne the expense of the support of the child, asking a judgment in a sum sufficient to cover one-half of the expenses of such support during the minority of the child.

It is contended by the defendant that, through inadvertence and mistake, the decree in the original divorce action did not express the true decision arrived at by the trial court, and that it was intended that the property awarded to the plaintiff in that action should be used by her in supporting the child, and that the decree should have so provided. This matter was plead as the first affirmative defense. The second affirmative defense was that the matter of the support of the child was res judicata, having been a matter involved in a prior suit.

We have held in Gibson v. Gibson, 18 Wash. 489, 51 Pac. 1041, 40 L. R. A. 587; Ditmar v. Ditmar, 27 Wash. 13, 67 Pac. 353, 91 Am. St. 817; Hector v. Hector, 51 Wash. 434, 99 Pac. 13, that, where the decree of divorce does not provide for the maintenance of a child, a separate action can be waged by the mother to whom the custody of such child had been granted, for the purpose of recovering from the father his share of the expense of the maintenance of the minor during its minority. The defendant, recognizing this rule by the affirmative defense interposed by him in this action, attempts to escape its operation by offering to show that *363the decree in the original divorce action did not properly express the conclusion of the court, and attempts to have that decree changed in this suit. This effort to reform the original decree is a collateral attack upon that decree; Peyton v. Peyton, 28 Wash. 278, 68 Pac. 757; Hicks v. Hicks, 69 Wash. 627, 125 Pac. 945; Bayer v. Bayer, 83 Wash. 430, 145 Pac. 433, and cannot succeed. The defendant’s remedy, if the decree did not speak the truth, was to have made a direct attack upon it in the action in the court where it was entered. He cannot now be heard to attack it in this manner in this action.

The judgment of the lower court will be affirmed.