A base seat for being used with a bed, a chair, or a sofa, the base seat comprising: a fixation base having a front frame body and a rear frame body; a first rocking mount connected with the front frame body and the rear frame body of the fixation base via two front suspension arms and two rear suspension arms, respectively, in a way that each of the two front suspension arms has a top end pivotally connected with the front frame body and a bottom end pivotally connected with the first rocking mount in a way that a first distance between the top ends of the two front suspension arms is smaller than a second distance between the bottom ends of the two front suspension arms, and each of the two rear suspension arms has a top end pivotally connected with the rear frame body and a bottom end pivotally connected with the first rocking mount in a way that a first distance between the top ends of the two rear suspension arms is smaller than a second distance between the bottom ends of the two rear suspension arms, such that the first rocking mount is swingable leftward and rightward relative to the fixation base along a first arc path with a variable inclined angle thereof; the first rocking mount comprising a right frame body and a left frame body; a first drive device disposed between the fixation base and the first rocking mount to drive the first rocking mount to reciprocatingly swing leftward and rightward relative to the fixation base; characterized in that a second rocking mount connected with the left frame body and the right frame body of the first rocking mount via two left suspension arms and two right suspension arms, respectively, in a way that each of the two left suspension arms has a top end pivotally connected with the left frame body and a bottom end pivotally connected with the second rocking mount in a way that a third distance between the top ends of the two left suspension arms is smaller than a fourth distance between the bottom ends of the two left suspension arms, and each of the two right suspension arms has a top end pivotally connected with the right frame body and a bottom end pivotally connected with the second rocking mount in a way that a third distance between the top ends of the two right suspension arms is smaller than a fourth distance between the bottom ends of the two right suspension arms, such that the second rocking mount is swingable forward and backward relative to the first rocking mount along a second arc path with a variable inclined angle thereof; the second rocking mount being configured to support the bed, the chair or the sofa; and a second drive device disposed between the first rocking mount and the second rocking mount to drive the second rocking mount to reciprocatingly swing forward and backward relative to the first rocking mount. a fixation base having a front frame body and a rear frame body; a first rocking mount connected with the front frame body and the rear frame body of the fixation base via two front suspension arms and two rear suspension arms, respectively, in a way that each of the two front suspension arms has a top end pivotally connected with the front frame body and a bottom end pivotally connected with the first rocking mount in a way that a first distance between the top ends of the two front suspension arms is smaller than a second distance between the bottom ends of the two front suspension arms, and each of the two rear suspension arms has a top end pivotally connected with the rear frame body and a bottom end pivotally connected with the first rocking mount in a way that a first distance between the top ends of the two rear suspension arms is smaller than a second distance between the bottom ends of the two rear suspension arms, such that the first rocking mount is swingable leftward and rightward relative to the fixation base along a first arc path with a variable inclined angle thereof; the first rocking mount comprising a right frame body and a left frame body; a first drive device disposed between the fixation base and the first rocking mount to drive the first rocking mount to reciprocatingly swing leftward and rightward relative to the fixation base; characterized in that a second rocking mount connected with the left frame body and the right frame body of the first rocking mount via two left suspension arms and two right suspension arms, respectively, in a way that each of the two left suspension arms has a top end pivotally connected with the left frame body and a bottom end pivotally connected with the second rocking mount in a way that a third distance between the top ends of the two left suspension arms is smaller than a fourth distance between the bottom ends of the two left suspension arms, and each of the two right suspension arms has a top end pivotally connected with the right frame body and a bottom end pivotally connected with the second rocking mount in a way that a third distance between the top ends of the two right suspension arms is smaller than a fourth distance between the bottom ends of the two right suspension arms, such that the second rocking mount is swingable forward and backward relative to the first rocking mount along a second arc path with a variable inclined angle thereof; the second rocking mount being configured to support the bed, the chair or the sofa; and a second drive device disposed between the first rocking mount and the second rocking mount to drive the second rocking mount to reciprocatingly swing forward and backward relative to the first rocking mount.