To provide a grinding device for a cylinder bore capable of forming the inner peripheral surface of the cylinder bore to an arbitrary non-circular shape while restraining the structure of a grinding tool and the control in grinding from being complexed.

A moving control unit 39 moves the grinding tool 29 in accordance with a predetermined path, a rotating control unit 38 rotates the grinding tool 29, a temperature control unit 41 controls to approximate the temperature of the grinding liquid before flowing in the grinding tool 29 to the target prescribed temperature in response to the position of the grinding tool 29 in a predetermined path, and grinds the inner peripheral surface 43a of the cylinder bore 43 by contacting a grinding working surface portion 56 with the inner peripheral surface 43a of the cylinder bore 43.