A vehicular heat management system is provided with: a switch unit (21, 22) that switches states between a state such that a heating medium is circulated between a heating medium cooling heat exchanger (14) and each of heat generating devices such as a heating medium/outer air heat exchanger (13), an engine heat transfer unit (18), and an inverter (19), and a state such that the heating medium is circulated between a heating medium heating heat exchanger (15) and each of the heat generating devices; a flow rate adjusting unit (21, 22) that adjusts a flow rate of the heating medium with respect to each of the heating medium/outer air heat exchanger (13) and the engine heat transfer unit (18); an air conditioning request unit (88) that makes a cooling request for cooling blower air with the air cooling heat exchanger (16), and a heating request for heating the blower air with the air heating heat exchanger (17); and a control device (70) that controls the activation of at least one of the switch unit (21, 22), a compressor (32), and the flow rate adjusting unit (21, 22) on the basis of the presence or absence of the cooling request and the presence or absence of the heating request from the air conditioning request unit (88).