Gripping method for turbocharger housing and work gripping device

A work gripping device comprising:

• a body that is cylindrical and of which one end side is a work attaching side;
• a plunger that is provided in an inner hole of the body such as to be allowed to move back and forth along an axial direction of the body;
• a jaw that includes a gripping surface that grips a work and is provided on an end surface of the body on the work attaching side such as to move back and forth along a radial direction of the body in tandem with movement of the plunger;
• and
• a pusher that presses the work in a direction away from the body in accompaniment with a movement of the plunger to the work attaching side, wherein,
• the jaw includes a contact surface that projects in an outward radial direction of the body from an end edge of the gripping surface away from the body,
• the pusher presses the work to the contact surface in accompaniment with the movement of the plunger to the work attaching side,
• the gripping surface grips an inner diameter of the work, and
• the pusher is provided in the plunger such as to be allowed to move along a movement direction of the plunger and is provided such as to be allowed to move along the movement direction of the plunger by fluid pressure, in addition to the movement of the plunger.