A piezoelectric actuator (1) includes: a piezoelectric element (3); and a first frictional portion (10) and a second frictional portion (12) that are disposed on one principal surface (2d) of the piezoelectric element (3). The first frictional portion (10) is disposed at a position other than the antinodes of the piezoelectric element (3) at which a distance from one of the end surfaces (2a) is less than ⅓ L, where L represents a length in the longitudinal direction of the piezoelectric element (3). The second frictional portion (12) is disposed at a position other than the antinodes of the piezoelectric element (3) at which a distance from the other of the end surfaces (2b) is less than ⅓ L.