Father’s Network Scotland (FNS) said they had been inundated with growing calls every month from men who were in crisis.
But the charity fears many could be missing out on help because they don’t know where to turn.
The organisation said the mental health support they offer has been “touch and go” due to a hole in funding caused by Covid delays.
The new app, funded by Movember as part of a £3.5 million global initiative, will allow men across Scotland to get 24/7 support by connecting instantly with NHS and other community services local to them.
Men will also be able to access a chat area where they can speak to peers, as well as advice and content on mental health support.
During international men’s mental health week, which kicks off today, FNS is calling for urgent mental health checks for all new fathers in Scotland.
The Edinburgh-based charity led Scotland’s first training programme helping midwives carry out mental health checks for dads.
In a recent survey, 37 per cent of fathers told FNS their mental health was bad or very bad.
Suicide is the leading cause of death in men aged 20-49 in the UK and men are three times more likely to die by suicide than women.
Men are also significantly less likely to seek support for mental health problems, only accounting for 36 per cent of referrals to NHS talking therapies.
Kirsty Nicholls, project lead for the app at Fathers Network Scotland, said: "We still have outdated gender stereotypes and there’s a pressure on men to not open up about their emotions.
“This funding will transform support that Fathers Network Scotland is able to offer men across Scotland. The numbers who are reaching out to us is growing every month.
“We hear from dads who are dealing with relationship breakdown, negotiating the family court system, missing children they are denied access to, or dealing with the loss of a child.
“The app will mean that any man who is facing mental health challenges will be able to receive help 365 days a year and make strong social connections when they are most needed.
"We are a small team of four, but we have kept our mental health support going in recent months with zero funding, so it has been touch and go. With the app, even if men get in touch in crisis in the middle of the night they will be able to see services locally and be reassured that help is going to be available to them.”
The app will be developed over two years, but the aim is to get it up and running within the first year. It is is one of 11 projects funded by Movember’s Social Connections Challenge.
Brendan Maher, global mental health director at Movember, said: “We were looking for technology-based ideas to address the problem of loneliness and isolation. We’re really looking forward to working with Fathers Network Scotland to develop this app, which will support the mental wellbeing of dads who have been struggling in the most difficult circumstances.”