The present invention provides a phase shifter, comprising a cavity, and a fixed circuit board and a phase shift unit that are located in the cavity. The phase shift unit can move relative to the fixed circuit board. A power division circuit is disposed on the fixed circuit board. The power division circuit comprises an input end, a main feeder, a node, at least two output ends, a filter branch and at least two output circuits. The main feeder is electrically connected between the input end and the node. The filter branch is electrically connected to the main feeder, and the filter branch is in the shape of an open circuit. The at least two output circuits are electrically connected between the node and the at least two output ends, respectively. The phase shift unit and the at least two output circuits are disposed oppositely, and the phase shift unit is configured to change phase values from the node to the at least two output ends. The present invention also provides an antenna. Byintegrating a filter branch into a phase shifter, the present invention reduces the costs of an antenna, simplifies the connection of a main feed network, and improves the magnitude or stability of PIM.