To provide a baby carriage which can conveniently be carried around upon folding up.

An X frame 12 is spread horizontally in the service position of baby carriage and a main seat supporting frame 38 is coupled pivotally with the front parts 22 and 24 of the base X frame 12 and a supporting frame pivoted on the tails 78 and 80 of the base X frame 12 and coupled pivotally by the main seat supporting frame 38 is coupled. A latch to maintain the body carriage in service condition folds up the base X frame 12 in the crosswise direction for storage or transportation and enables the main seat supporting frame 38 and the supporting frame can be folded up in the vertical direction toward the base X frame folded up.