To provide a hood flip-up device capable of quickly and stably pushing a rear end of a hood panel upward in operation.

The hood flip-up device U includes a constitution to raise a rear end of a hood panel 10 by pushing an upper end of a rising piston rod 45 of an actuator 21 upward in contact with a lower side of a rear end of a hood panel 10. The piston rod 45 includes a push-up part 55 coming into contact with a receiving part 16 provided to the hood panel 10 and pushing up the rear end of the hood panel 10 together with a receiving part 16 on an upper end. A receiving face 16a receiving the push-up part 55 is inclined in a push-up direction of the piston rod 45. A push-up face 57b plastically deformed to be parallel to the receiving face 16a on a cross section along a forward and backward direction when the push-up part 44 comes into contact with the receiving part 16, and extending in the forward and backward direction and capable of sliding in contact with the receiving face 16a is formed.