The present invention has an object to effectively prevent deterioration of combustion characteristics when engine temperature is low. There is provided an intake pressure controller 24 that effects control such that, when an operating condition discriminator 21 that identifies engine temperature identifies low engine temperature after engine start-up, control by an engine controller (feedback controller 23) that performs engine control on fluctuation of intake negative pressure to decrease the intake negative pressure is suppressed until the temperature of the intake passage rises to at or above a predetermined value, and such that the intake negative pressure is made larger.