To provide a ready-mixed concrete charger for filling efficiently a storage space of a delivery section with ready mixed concrete.

A delivery section 4 for delivering ready mixed concrete 1 is formed of a peripheral wall 6 and a rotor 7 in the peripheral wall 6. An opening 6a communicating with a storage section 5 is formed on the upper side of the peripheral wall 6, while a charging hole 6b for charging the ready mixed concrete 1 is formed on the lower side. A storage space 4a for storing the ready mixed concrete 1 is formed on the rotor 7, and the ready mixed concrete 1 is rotated to transfer from a first position in which the storage space 4a faces the opening 6a to a second position in which the storage space 4a faces the charging hole 6b. An air vent from which air in the storage space 4a is discharged when the ready mixed concrete 1 flows from the opening 6a into the storage space 4a is formed on the peripheral wall 6.