The present invention provides a shower door adjusting device and a shower door. The shower door adjusting device comprises: a first side frame and a second side frame, one of which is a fixed side frame (10) and the other of which is an adjustable side frame (11); a first fixing base assembly including a first fixing base (12) and a second fixing base (14), wherein the first fixing base (12) is fixed on the first side frame, the second fixing base (14) is detachably fixed on the first fixing base (12), an installation groove (158) is formed in the first and second fixing bases, and the first fixing base assembly is provided with a first through groove (126) therein; a locking sheet (16) whose end is provided with a boss (161, 162), wherein the end of the locking sheet is installed in the installation groove (158), the locking sheet (16) is provided with a first locking hole (164, 168) which faces the first through groove (126), a spring abutting (185) against the boss (161, 162) is provided to the first fixing base assembly, the boss (161, 162) is provided with a threaded hole (163, 169), a screw (18) passing through the threaded hole (163, 169) is provided to the first fixing base assembly, and one end of the screw (18) close to the first fixing base (12) is provided with an abutting portion (182); and a first connecting bar (19) fixed to the second side frame and provided with a first rack (195) passing through the first locking hole (164, 168) and the first through groove (126), wherein after the abutting portion of the screw (18) abuts against the first fixing base (12), the first rack (195) is locked within the first locking hole (164, 168). The shower door comprises the shower door adjusting device and a glass panel (3) provided within the adjustable side frame (11).