We have proposed finger rehabilitation robot for in-home hemiplegic patient. In previous study, there remained the problem of not being able to complete treatment in one robot according to degree of recovery due to the housing. This problem leads to another problem such as asking multiple expensive robot, making home rehabilitation difficult. To solve this problem, we have developed the robot that can treat various degree of recovery in one device. In detail, our robot has been developed focusing on (i) the housing that can be customizable according to degree of recovery and (ii) the assist mechanism that can properly assist finger extension whatever load is applied according to pathological grip due to hemiplegia. Our experimental result confirming the upper limit of assist force supposed that our robot has enough force to assist finger extension under load that could conceivably be based on the force of young adult males.