A hinge mechanism and a foldable ergonomic keyboard having the same are disclosed. The hinge mechanism includes a pair of operating modules and a linking unit. Each operating module has an accommodating housing, a locking assembly received in the accommodating housing, a latch member connected to one end of the accommodating housing for controlling a displacement of the locking assembly, and a spherical member received in the accommodating housing. The other end of the accommodating housing is formed with a positioning slot. The linking unit has two ends respectively passed through the positioning slots and connected to the spherical members. The hinge mechanism connects two input sections via the accommodating housings, and the latch member can selectively arranged to press tightly the spherical member in the accommodating housing or release the spherical member. Thus, the two input sections can be adjusted in different postures or folded condition.