We propose a novel method by which a daily assistive robot can learn a new task from a user with no technical knowledge. The system is inspired by Mitate, the human capacity to communicate the movement of a tool using a different tool in a different environment. We confirmed experimentally that the system can learn a new trajectory of an object in the hand according to the online instruction by a human teacher, even if the prior knowledge about the object in the teacher's hand is not presented and the object is different from the manipulated object. These findings are not only desired in robotic support for elderly or handicapped people but also helpful for an intelligent robot system to enable human-like robust and diverse motion learning.