An optical scanning apparatus comprising: an optical deflection device, comprising: a pair of zig-zag beams (22a, 22b), each of the zig-zag beams (22a, 22b) including a plurality of first beams and a plurality of second beams arranged with a zig-zag pattern; a frame to support the zig-zag beams (22a, 22b); a reflection mirror, supported by the zig-zag beams (22a, 22b), to deflect light; a plurality of piezoelectric elements disposed on the first beams and the second beams of the zig-zag beams (22a, 22b); a voltage application unit to apply a first waveform voltage to the piezoelectric elements disposed on the first beams, and a second waveform voltage to the piezoelectric elements disposed on the second beams to flexibly deform the first beams and the second beams of the zig-zag beams (22a, 22b), wherein the reflection mirror is oscillatable by the flexible deformation of the first beams and the second beams, the apparatus characterized by: a memory storing the measured piezoelectric constant with respect to changed applied voltage as information relating to the variation of the piezoelectric constant with respect to applied voltage; a control unit to control the voltage application unit to apply a time-varying waveform voltage to the piezoelectric elements, to set the oscillation of the reflection mirror at a constant speed, wherein the time-varying waveform voltage is corrected by the control unit based on said information stored in the memory. an optical deflection device, comprising: a pair of zig-zag beams (22a, 22b), each of the zig-zag beams (22a, 22b) including a plurality of first beams and a plurality of second beams arranged with a zig-zag pattern; a frame to support the zig-zag beams (22a, 22b); a reflection mirror, supported by the zig-zag beams (22a, 22b), to deflect light; a plurality of piezoelectric elements disposed on the first beams and the second beams of the zig-zag beams (22a, 22b); a voltage application unit to apply a first waveform voltage to the piezoelectric elements disposed on the first beams, and a second waveform voltage to the piezoelectric elements disposed on the second beams to flexibly deform the first beams and the second beams of the zig-zag beams (22a, 22b), wherein the reflection mirror is oscillatable by the flexible deformation of the first beams and the second beams, a pair of zig-zag beams (22a, 22b), each of the zig-zag beams (22a, 22b) including a plurality of first beams and a plurality of second beams arranged with a zig-zag pattern; a frame to support the zig-zag beams (22a, 22b); a reflection mirror, supported by the zig-zag beams (22a, 22b), to deflect light; a plurality of piezoelectric elements disposed on the first beams and the second beams of the zig-zag beams (22a, 22b); a voltage application unit to apply a first waveform voltage to the piezoelectric elements disposed on the first beams, and a second waveform voltage to the piezoelectric elements disposed on the second beams to flexibly deform the first beams and the second beams of the zig-zag beams (22a, 22b), wherein the reflection mirror is oscillatable by the flexible deformation of the first beams and the second beams, the apparatus characterized by: a memory storing the measured piezoelectric constant with respect to changed applied voltage as information relating to the variation of the piezoelectric constant with respect to applied voltage; a control unit to control the voltage application unit to apply a time-varying waveform voltage to the piezoelectric elements, to set the oscillation of the reflection mirror at a constant speed, wherein the time-varying waveform voltage is corrected by the control unit based on said information stored in the memory. a memory storing the measured piezoelectric constant with respect to changed applied voltage as information relating to the variation of the piezoelectric constant with respect to applied voltage; a control unit to control the voltage application unit to apply a time-varying waveform voltage to the piezoelectric elements, to set the oscillation of the reflection mirror at a constant speed, wherein the time-varying waveform voltage is corrected by the control unit based on said information stored in the memory.