A shift controller controls a transmission for a hybrid vehicle in which: an engine and a motor are connected together via a clutch; and the transmission is placed between the motor and driving wheels. The shift controller has: a first shift controlling unit which performs shift control on a basis of at least one of transmission efficiency of the transmission and power generation efficiency of the motor in a case where regeneration is performed with the clutch disengaged during deceleration of the hybrid vehicle; and a second shift controlling unit which performs shift control to make a transmission gear ratio of the transmission smaller than in the shift control performed by the first shift controlling unit in a case where the regeneration is performed with the clutch engaged during the deceleration of the hybrid vehicle.