A resist removing agent and a resist removing composition, having an excellent capability for removing a resist and polymer and which does not attack underlying layers, a method for preparing the same and a resist removing method using the same. The resist removing agent includes alkoxy N-hydroxyalkyl alkanamide. The resist removing composition includes alkoxy N-hydroxyalkyl alkanamide, and at least one compound selected from a group consisting of a polar material having a dipole moment of 3 or greater, an attack inhibitor and alkanolamine. A substrate having the resist thereon is brought into contact with the resist removing agent or resist removing composition to remove the resist.