  Formation processes of high-mass stars have been long-standing issues in
astronomy and astrophysics. This is mainly because of major difficulties in
observational studies such as a smaller number of high-mass young stellar
objects (YSOs), larger distances, and more complex structures in young
high-mass clusters compared with nearby low-mass isolated star-forming regions
(SFRs), and extremely large opacity of interstellar dust except for centimeter
to submillimeter wavelengths. High resolution and high sensitivity observations
with Atacama Large Millimeter/Submillimeter Array (ALMA) at
millimeter/submillimeter wavelengths will overcome these observational
difficulties even for statistical studies with increasing number of high-mass
YSO samples. This review will summarize recent progresses in high-mass
star-formation studies with ALMA such as clumps and filaments in giant
molecular cloud complexes and infrared dark clouds (IRDCs), protostellar disks
and outflows in dense cores, chemistry, masers, and accretion bursts in
high-mass SFRs.
