1. A magnetic resonance imaging (MRI) apparatus comprising: an assembly of gantry components including static and gradient magnetic field generators and at least one radio frequency (RF) coil; and an MRI control system, connected to control the gantry components, including at least one RF transmitter, at least one RF receiver and one or more computer control circuits, the MRI control system being configured to: apply a spatially non-selective inversion pulse and a spatially selective excitation pulse, for distinguishably displaying inflowing blood flowing into an imaging region including myocardium; acquire a plurality of imaging data sets without administration of a contrast medium, each of the plurality of imaging data sets corresponding to a respective one of a plurality of different traveling times of inflowing blood flowing into the imaging region in synchronization with a heartbeat together with delay times form synchronization signals, by changing a time from application timing of the spatially selective excitation pulse to acquisition timing of each of the plurality of imaging data sets, wherein the delay times are set such that the time from application timing of the spatially selective excitation pulse to acquisition timing of each of the plurality of imaging data sets spans multiple heart beats for at least one of the acquisitions of the plurality of imaging data sets; and generate a plurality of blood flow image data sets, based on the acquired plurality of imaging data sets, wherein the MRI control system is further configured to set the delay times so as to include a first delay time and a second delay time, the first delay time being a time interval from a first R-wave to an application time of the spatially non-selective inversion pulse, and the second delay time being a time interval from a second R-wave immediately before data acquisition to a start time of the data acquisition.