To allow a treatment agent supplied to space in which asbestos is used to spread in all parts in the space.

In a method for confining asbestos, a treatment agent X for confining asbestos 2 is supplied into space 3 in which the asbestos 2 is used, to confine the asbestos 2. The method includes one or more treatment of: treatment agent supplying treatment of supplying the treatment agent X into the space 3 through an opening part 4 which communicates the outside of the space 3 with the inside of the space 3; exhausting treatment of exhausting air in the space 3 to the outside of the space 3 through the opening part 4; and air supplying treatment of supplying air into the space 3 through the opening part 4.