A data recording and reproducing device includes: a light emitting element that generates light and emits the light toward an optical recording medium; a light emission control section that feedback-controls an emitted light quantity from the light emitting element; a light attenuating drive section that includes a light attenuating section, and inserts the light attenuating section into an emission path of the light when reproducing data from the optical recording medium and retracts the light attenuating section from the emission path when recording data onto the optical recording medium; and a shock detecting section that detects a shock of a magnitude causing the light attenuating drive section to switch between the insertion and retraction. When the shock detecting section detects the shock during data recording, the light emission control section lowers a control target value of the emitted light quantity from a value set at the time of shock detection.