A method of controlling weft insertion of an air jet loom, the air jet loom including: a holding pin configured to hold and release a weft yarn that is used for weft insertion; and a weft insertion nozzle (6, 7, 8) that injects air for the weft insertion, wherein the weft yarn is inserted by lifting the holding pin to release the weft yarn and transferring the released weft yarn in a weft insertion direction with the air injected from the weft insertion nozzle (6, 7, 8), the method comprising the steps of: detecting a characteristic of the weft yarn that is yet to be inserted; predicting a weft yarn arrival timing (TWp) at which the weft yarn that is inserted in accordance with a specified weft insertion condition arrives at a specified position in the weft insertion direction, on the basis of the characteristic of the weft yarn that is detected in the detecting step; determining a difference between the predicted weft yarn arrival timing (TWp) that is predicted in the predicting step and a target weft yarn arrival timing (TWr); modifying only a lifting timing of the holding pin at which the holding pin is lifted in accordance with the difference between the predicted weft yarn arrival timing (TWp) and the target weft yarn arrival timing (TWr) that is determined in the determining step; and lifting the holding pin at the modified lifting timing that is modified in the modifying step to insert the weft yarn. a holding pin configured to hold and release a weft yarn that is used for weft insertion; and a weft insertion nozzle (6, 7, 8) that injects air for the weft insertion, wherein the weft yarn is inserted by lifting the holding pin to release the weft yarn and transferring the released weft yarn in a weft insertion direction with the air injected from the weft insertion nozzle (6, 7, 8), the method comprising the steps of: detecting a characteristic of the weft yarn that is yet to be inserted; predicting a weft yarn arrival timing (TWp) at which the weft yarn that is inserted in accordance with a specified weft insertion condition arrives at a specified position in the weft insertion direction, on the basis of the characteristic of the weft yarn that is detected in the detecting step; determining a difference between the predicted weft yarn arrival timing (TWp) that is predicted in the predicting step and a target weft yarn arrival timing (TWr); modifying only a lifting timing of the holding pin at which the holding pin is lifted in accordance with the difference between the predicted weft yarn arrival timing (TWp) and the target weft yarn arrival timing (TWr) that is determined in the determining step; and lifting the holding pin at the modified lifting timing that is modified in the modifying step to insert the weft yarn. detecting a characteristic of the weft yarn that is yet to be inserted; predicting a weft yarn arrival timing (TWp) at which the weft yarn that is inserted in accordance with a specified weft insertion condition arrives at a specified position in the weft insertion direction, on the basis of the characteristic of the weft yarn that is detected in the detecting step; determining a difference between the predicted weft yarn arrival timing (TWp) that is predicted in the predicting step and a target weft yarn arrival timing (TWr); modifying only a lifting timing of the holding pin at which the holding pin is lifted in accordance with the difference between the predicted weft yarn arrival timing (TWp) and the target weft yarn arrival timing (TWr) that is determined in the determining step; and lifting the holding pin at the modified lifting timing that is modified in the modifying step to insert the weft yarn.