PURPOSE: To enable efficient aging of a prescribed time without complicated control even if the number of cargoes conveyed in and out in a day differs from day to day, by providing a cargo convey-in/out method appropriate to an aging equipment in the assembly line of a home electric appliance or the like.

CONSTITUTION: In a rotary rack, frames 3, each of which has cargo carriers 2 at plural levels, are moved in an elliptic passage 4. A cargo 16 is transferred from a carry-in conveyor 13 onto a desired carrier 2 by a cargo put-in/out unit 8. A cargo 16 on a carrier 2 is taken out by a carry-out conveyor 14. The carriers 2 are provided with serial numbers I , II, III,... zigzag vertically. On the first day, the cargoes 16 are conveyed in onto the carriers in the order of the serial numbers. If the cargoes 16 are conveyed in up to the eleventh carrier 2 with the number of X I on the first day, new cargoes 16 are conveyed in starting with the twelfth carrier 2 after the convey-out of the preceding cargoes on the second day. Cargo convey-in/out work is thus effected starting with the (x+1)-th carrier on the third or other succeeding day, too, following the x-th carrier with which the preceding day's work was finished.