Bicycle saddle lifter

A bicycle saddle lifter comprising a fixed pipe (1) inserted in and fixed to a vertical pipe of a bicycle, a lifting rod (2) carrying a saddle on its top and slidably inserted in said fixed pipe (1), thereby allowing the saddle to be raised and lowered while a bicycle driver is sitting on the saddle, a link (5) through which said fixed pipe (1) and said lifting rod (2) are coupled together, a stroke spring (10) vertically upwardly biasing the lifting rod, said link (5) comprising a lower link piece (6) and an upper link piece (7), ratchet pawls (13a and 13b) for checking descent and ascent of the saddle, respectively, and corresponding ratchet gears (14), said ratchet pawls and said ratchet gears being provided at a portion where said upper and lower link pieces are coupled together, and being arranged such that the ratchet pawls (13a and 13b) are selectively brought into and out of engagement with the respective ratchet gears (14), so that the saddle lifter can be selectively switched over between a position where the saddle is allowed to descend and cannot ascend and a position where the saddle is allowed to ascend and cannot descend from its locked positions at predetermined heights, characterized in that the biasing force of the stroke spring (10) is determined such that when the weight of a bicycle driver directly acts on the saddle, the saddle lowers, and when the bicycle driver applies force to pedals of the bicycle while sitting on the saddle, and the load on the saddle decreases, the saddle rises, that while the bicycle driver is not sitting on the saddle, resistance resulting from the biasing force of the stroke spring (10) prevents the ratchet pawl (13b) for checking the ascent of the saddle from being disengaged from the corresponding ratchet gear (14) even by switchover operation, and that while the bicycle driver is sitting on the saddle, the biasing force of the stroke spring (10) is canceled by the load applied to the saddle and the resistance decreases, thereby allowing the ratchet pawl (13b) for checking the ascent of the saddle to be disengaged from the ratchet gear (14) by switchover operation.