A shift controller for an automatic transmission mechanism is configured such that when the engine is in a driven state in which the engine is driven by a travel inertia force or the like and an accumulated pressure amount of the accumulator is equal to or less than a predetermined threshold, the excessive engine brake force, which is generated due to the accumulation of at least a portion of the hydraulic pressure generated from the mechanical hydraulic pump in the accumulator, is inhibited or reduced by conducting upshifting that relatively decreases the gear ratio of the automatic transmission mechanism. Therefore, the generation of the excessive engine brake force can be inhibited or reduced even when the engine is in the driven state and pressure accumulation is performed.