A piezoelectric blower (100) includes a housing (17), a vibrating plate (41), and a piezoelectric element (42). The vibrating plate (41) forms a column-shaped blower chamber (31) together with the housing (17). The vibrating plate (41) and the housing (17) are formed so that the blower chamber (31) has a radius a. The piezoelectric element (42) causes the vibrating plate (41) to concentrically bend and vibrate at a resonance frequency f. A recessed portion (26) is formed in the housing (17) on the side facing the vibrating plate (41). The recessed portion (26) defines a cavity (25), which constitutes the blower chamber (31) and communicates with the vent hole (24). The radius a of the blower chamber (31) and the resonance frequency f of the vibrating plate (41) satisfy a relationship of 0.8×(k0c)/(2π)≤af≤1.2×(k0c)/(2π).