Lock-up device for torque converter

A lock-up device for a torque converter, the lock-up device being disposed between a front cover and a turbine in the torque converter to mechanically connect the front cover and the turbine, the lock-up device comprising:

• a clutch part disposed in a power transmission path from the front cover to the turbine, the clutch part being configured to be in a clutch-on state of transmitting a power from the front cover to the turbine in a set posture;
• and
• a release part configured to be actuated by a hydraulic pressure being increased in a space on a turbine-side of the piston to turn the clutch part from the clutch-on state to a clutch-off state and to block transmission of the power from the front cover to the turbine,
• the clutch part including
• an input-side member coupled to the front cover while being non-rotatable relative thereto,
• an output-side member coupled to the turbine while being non-rotatable relative thereto,
• a friction member being mounted to either the input-side member or the output-side member, and
• a pressing member configured to press the friction member between the input-side member and the output-side member when the hydraulic pressure is not being applied to the release part, and
• the release part including a piston configured to release pressing of the pressing member when the hydraulic pressure is applied to the release part.