Provided is a phase shifter that shifts a phase of an input signal based on switching between a low-pass filter and a high-pass filter, the phase shifter including: a first field-effect transistor that is coupled between an input terminal and an output terminal; a resonance circuit that resonates when the first field-effect transistor is in an on-state; an additional line that is coupled between the resonance circuit and a node that is included in a signal line, which is formed between the input and output terminals when the first field-effect transistor is in the on-state; and an inductor that is included in a part of the signal line and forms a low-pass filter together with at least the additional line, when the first field-effect transistor is in the on-state.