To provide a method for changing a main rope on a carrier, and a main rope changing device, in which main rope changing work that has been conventionally conducted manually for each rope can be conducted for a plurality of ropes at a time to largely reduce necessary time and labor.

This method is provided with a process of stopping a car at a position where a worker can get onto the ceiling of the car from a landing floor 4 at the top floor, a process of installing a rope winch 15 for feeding a main rope close to a rope shackle 12a of a car side main rope at an upper part of an elevator shaft, a process of moving both ends of an old main rope 10 off the rope shackle 12a and 12b, putting a car side rope end 10a through the rope winch 15 down to a lower part of the elevator shaft, and connecting a weight side rope end to a tip 7a of a new main rope 7 taken from a rope supply device 6 installed on the lowest floor landing 3 by a connection device 23, and a process of driving the rope winch 15 to recover the old main rope 10 at the lowest floor landing while replacing it with a new main rope 7.