Patent ID: 10966530

Abstract:
A backrest (7) includes: a tensile material (71) on which a load support surface (71f) configured to receive a load of a seated person is formed; a back front frame (80F) that supports an outer peripheral end portion (71e) of the tensile material (71); an attachment portion (87) which is formed in the back front frame (80F) and faces the tensile material (71) in a state where the attachment portion (87) is separated from the tensile material (71) in a direction intersecting the load support surface (71f); and a lumber support (200) that is attachable to and detachable from the attachment portion (87), in which the lumber support (200) includes an attaching portion (222) which extends in a direction along the load support surface (71f), is inserted into a gap (S) between the tensile material (71) and the attachment portion (87), and is fixed to the attachment portion (87).