Linear actuator and hair cutting device

A linear actuator, comprising:

• at least one electromagnet arranged horizontally, wherein each electromagnet comprises two magnetic poles, and the two magnetic poles are arranged at two ends of the electromagnet along an axial direction of the electromagnet;
• and
• magnet groups disposed at two sides of the at least one electromagnet separately, wherein each magnet group is opposite to a corresponding one of the magnetic poles of the at least one electromagnet, each magnet group comprises at least two magnets, a side of a part of the at least two magnets facing the at least one electromagnet is S pole, and a side of another part of the at least two magnets facing the at least one electromagnet is N pole;
• after energizing the at least one electromagnet, the magnet groups are driven to reciprocate along a direction perpendicular to a central axis of the at least one electromagnet through magnetic induction action between the at least one electromagnet and the magnet groups.