A drive system for a hybrid vehicle, the drive system comprising: an internal combustion engine; a first motor configured to generate electric power, using power produced by the internal combustion engine; a second motor configured to operate with electric power generated by the first motor, so as to produce driving force; an output part configured to deliver driving force for driving the hybrid vehicle to which the driving force produced by the second motor is added, the power produced by the internal combustion engine being split into a first portion directed to the first motor and a second portion directed to the output part; a first planetary gear mechanism (14, 14a) including a first input element, a first reaction-force element, and a first output element, the first planetary gear mechanism (14, 14a) being configured to perform differential operation by the first input element, the first reaction-force element, and the first output element, the first input element being configured to receive driving force produced by the internal combustion engine, the first reaction-force element being coupled to the first motor; a second planetary gear mechanism (15, 15a) including a second input element, a second output element, and a second reaction-force element, the second planetary gear mechanism (15, 15a) being configured to perform differential operation by the second input element, the second output element, and the second reaction-force element, the second input element being coupled to the first output element, the second output element being coupled to the output part; a first clutch mechanism configured to selectively couple the first input element with the second reaction-force element; and a first brake mechanism provided between the second reaction-force element and a fixed member, the first brake mechanism being configured to selectively inhibit rotation of the second reaction-force element, characterized in that the drive system is arranged to add, at a driven gear, the driving force produced by the second motor to a driving force delivered from the output part. an internal combustion engine; a first motor configured to generate electric power, using power produced by the internal combustion engine; a second motor configured to operate with electric power generated by the first motor, so as to produce driving force; an output part configured to deliver driving force for driving the hybrid vehicle to which the driving force produced by the second motor is added, the power produced by the internal combustion engine being split into a first portion directed to the first motor and a second portion directed to the output part; a first planetary gear mechanism (14, 14a) including a first input element, a first reaction-force element, and a first output element, the first planetary gear mechanism (14, 14a) being configured to perform differential operation by the first input element, the first reaction-force element, and the first output element, the first input element being configured to receive driving force produced by the internal combustion engine, the first reaction-force element being coupled to the first motor; a second planetary gear mechanism (15, 15a) including a second input element, a second output element, and a second reaction-force element, the second planetary gear mechanism (15, 15a) being configured to perform differential operation by the second input element, the second output element, and the second reaction-force element, the second input element being coupled to the first output element, the second output element being coupled to the output part; a first clutch mechanism configured to selectively couple the first input element with the second reaction-force element; and a first brake mechanism provided between the second reaction-force element and a fixed member, the first brake mechanism being configured to selectively inhibit rotation of the second reaction-force element, characterized in that the drive system is arranged to add, at a driven gear, the driving force produced by the second motor to a driving force delivered from the output part.