Mat-type exercise device

A mat exercise device comprising:

• a device body which includes a seating part;
• a plurality of wheel modules installed in the device body such that each of the plurality of wheel modules is capable of moving between a protrusion position at which the corresponding wheel module protrudes more downward than the seating part so as to move the device body, and a retraction position at which the corresponding wheel module moves more upward than the seating part to allow the seating part to be in contact with a floor;
• a plurality of switching modules which switches a position of at least one of the plurality of wheel modules between the protrusion position of the at least one of the plurality of wheel modules and the retraction position of the at least one of the plurality of wheel modules;
• and
• a plurality of safety modules which respectively moves the plurality of wheel modules to the retraction position in response to additional weight so that the seating part is in contact with the floor when the additional weight is respectively applied to the plurality of wheel modules.