To obtain a desired lock-up torque capacity by lowering a hydraulic oil pressure and reduces the rate of change in torque with respect to the hydraulic oil pressure in a lock-up device.

The lock-up device for the torque converter includes a piston 30, a clutch 31, a first oil pressure chamber Q1, a second oil pressure chamber Q2, a first oil pressure port P2, and a second oil pressure port P3. The first oil pressure chamber Q1 is formed between a front cover 2 and the piston 30 so that the hydraulic oil to operate the piston 30 is supplied to the chamber Q1. The second oil pressure chamber Q2 is formed independently of the first oil pressure chamber Q1 on the same side as in the first oil pressure chamber Q1 with respect to the piston 30 so that the hydraulic oil to operate the piston 30 is supplied to the chamber Q2. The first oil pressure port P2 supplies the hydraulic oil to the first oil pressure chamber Q1. The second oil pressure port P3 is provided independently of the first oil pressure port P2 so that the hydraulic oil is supplied to the second oil pressure chamber Q2.