This invention provides a control apparatus for an automatic transmission, which includes a plurality of engaging mechanisms. The plurality of engaging mechanisms include a mechanical engaging mechanism configured to function as a brake. The mechanical engaging mechanism can be switched between a first state in which rotation of a rotational element is restricted only in one direction and a second state in which the rotation is restricted in both directions. When switching from the first state to the second state, the control apparatus executes engagement control to set a plurality of hydraulic friction engaging mechanisms in an engaging state. In the engagement control, oil pressure supply control changes depending on the vehicle speed.