Child safety seat

A child safety seat comprising:

• a seat body whereon a seat space is defined;
• a headrest movably disposed on a front side of the seat body facing the seat space;
• a headrest adjusting mechanism for allowing the headrest to move relative to the seat body or restraining the headrest from moving relative to the seat body,
• the headrest adjusting mechanism comprising:
• at least one first engaging component slidably disposed on the headrest and partially exposed out of a front side of the headrest facing the seat space;
• and
• at least one second engaging component disposed inside the seat body;
• and
• a harness component comprising:
• a first part at least partially received between the headrest adjusting mechanism and the seat body;
• and
• a second part connected to the first part and exposed out of the headrest toward the seat space;
• wherein the headrest is restrained from moving relative to the seat body when the at least one first engaging component slides to engage with the at least one second engaging component, and the headrest is allowed to move relative to the seat body when the at least one first engaging component slides to disengage from the at least one second engaging component.