A chucking device includes a turntable fixed to a shaft having a central axis and a cone arranged axially above the turntable. An annular yoke is arranged above a sliding portion of the cone and fixed to the shaft, and a clamp magnet is fixed to the yoke through an adhesive agent. The yoke includes an upper surface having an annular recess defined in a concentric relationship with the central axis, the adhesive agent being applied on a region of the upper surface existing radially inwards of the recess. The recess includes a radial outer wall parallel to the central axis and a radial inner wall inclined radially inwards and axially upwards. The angle between the radial outer wall and a lower surface of the clamp magnet is greater than the angle between the radial inner wall and the lower surface of the clamp magnet.