The present invention provides a biped walking mobile apparatus, its walk controller, and walk controlling strategy therefor, which are to realize walk stability even under the road surface condition where the foot stance is unstable, for example, such as wet floor, ice, mud, or the carpet of long hair, or when only a part contacts with the floor surface due, for example, to its roughness. A walk controller (30) of the biped walking mobile apparatus comprises the force sensors (23L, 23R) for detecting the forces applied to soles of respective foot portions (14L, 14R) which drive-control the drive means of the respective joint portions (15L, 15R to 20L, 20R) of respective leg portions of the biped walking mobile apparatus based on gait data, and the compensation part (32) for correcting gait data from the gait forming part (24) based on horizontal floor reaction force among the forces detected by the force sensors, and it is constituted so that each force sensor (23L, 23R) comprises 3-axis force sensors set to each part of the soles of each foot portion (14L, 14R) divided in plurality.