Nearly 100 children aged 10 to 14 killed themselves in the UK in the past decade, according to the Office for National Statistics.
Charities said the numbers are a "national scandal" and called for the taboo of talking about suicide to be broken down.
Figures published for the first time show that 98 children under 15 have killed themselves in the UK from 2005 to 2014. Of these, 59 were boys and 39 were girls.
Children under 10 are not recognised in suicide figures and therefore not included.
Ged Flynn, the chief executive of the Papyrus prevention of young suicide charity, told the Press Association: "We have 'hidden' the fact that children and young people die this way because it is so flipping painful for us.
"It is painful and toxic to think about it, so we hide it and hope it goes away. Today we can see it is not going away.
"It is a national scandal and we have to talk about it."
He said experts have known for some time that depression starts for some at an early age, and there are a "plethora of reasons" why children take their own lives.
But the issue threaded through all cases is that the children feel "trapped or ashamed" by whatever is driving their suicidal thoughts.
He said the onus should not always be on the suicidal person to have to seek help, and urged those worried about someone to simply ask them how they are.
Mr Flynn said: "We think by asking them we will cause the problem so we keep quiet about it. But by asking you release that head of steam and enable that person who is suicidal to talk about it."
An NSPCC spokesman said: "Our ChildLine service has seen a huge increase in calls from desperately unhappy children.
"Last year more than half of the young people we referred to other agencies were suicidal.
"No child should ever feel so helpless that they find themselves in this awful situation. We all have a part to play in helping a young person before they reach crisis point. It is vital that children can speak up and any young person who wants to talk can call ChildLine on 0800 1111."
:: For confidential support and advice you can also contact the Papyrus charity's helpline on 08000684141
A Department of Health spokesman said: "Every death by suicide is a tragedy and is devastating for families, friends and communities.
"Our Suicide Prevention Strategy brings together all government departments to work at preventing these deaths.
"Alongside this we are investing almost £1 billion in providing mental health support in A&E and home based crisis care and soon, the NHS will be publishing its plan to improve mental health care, which will look at reducing suicides."